By Bob Goemans
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The 'LIVING' Marine Aquarium Manual

Basic and Advanced Husbandry for the 'Modern' Marine Aquarium

by Bob Goemans

Chapter 6 - Materials & Products

There are numerous items, e.g., objects, products, materials, mediums/media, or just plain-old 'stuff' that is generally needed when setting up and maintaining an aquarium. Besides these items, their proper usage and/or positioning are important and where appropriate, it also will be discussed. To further simplify their association, lets divide them into two categories; those that are generally used during the construction of a new system, and those used to maintain it once up and running.

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Construction Materials

Probably one of the most important is the piping that will transport water to and from the aquarium. Therefore, lets begin here with a few of the more popular types and its fittings, then move on to items such as the sand, rock and others that may be used to decorate its interior.


When planning almost any type aquarium there's always some form of piping to take into consideration since the health of aquarium inhabitants often depend on water motion, therefore, some form of piping is used to deliver it where needed. Many systems simply use PVC piping and fittings or vinyl tubing, but keep in mind that each joint/connection slightly reduces water flow and that long lengths of piping can reduce flow rates dramatically.

PVC (Polyvinyl Chloride)

The most popular form of piping by far is PVC pipe that come in several wall thicknesses, most often designated as Schedule 20, Schedule 40, or Schedule 80. The 20 versions is a thin walled material generally used in low-pressure situations, and possibly useful in aquaria for overflow standpipes. Schedule 80 has the thickest wall, yet the same outside diameter as Schedule 40, and is used where pressures are the greatest, such as over 60 psi. That leaves Schedule 40, which is quite fitting for almost all aquarium purposes.

This rigid white in color pipe is widely available in .5 inch (1.25 cm) to more than 6 inch (15 cm) ID's (internal diameter) widths and 10 foot (3 m) lengths and is easy to cut and by using specific cleaners, primers and cements made for this purpose, attach fittings for various purposes.

There are also more expensive stronger forms of this material for carrying drinking/hot water, e.g., CPVC (Chlorinated Polyvinyl Chloride), however there's no reason to use it, as regular PVC is perfectly acceptable for aquarium use. There is also a less expensive form of piping called ABS (Acrylonitrile Butadiene Styrene). This black piping is used in the construction field for waste removal, e.g., human waste, wastewater, and/or vent applications, however may contain anti-bacterial/fungus agents, therefore it's not recommended for aquarium use.

There's also a flexible form of PVC generally available in .5 inch (1.25 cm) to 3 inch (7.5 cm) ID's. It can be found in home-improvement stores where the required length can be cut from the long rolls usually hanging somewhere in their plumbing department. There are however, some concerns with this material, with one being only special cement can be used to attach it to rigid PVC. In my opinion this type connection, i.e., to regular hard PVC fittings, should not be used in 'pressure' situations such as connected to the outlets of high pressure water pumps as it tends to separate over time. Keep in mind the glue used to cement hard fittings to hard piping dries hard, but the glue used to connect flexible piping remains somewhat flexible, i.e., in a somewhat semi-ridge state to allow flexible PVC to move slightly. Furthermore, flexible piping is a ribbed material that allows for its flexibility and therefore internal water flow experiences some turbulence as it passes through, possibly somewhat reducing flow rate and adding pressure to inline fitting connections. Nevertheless, I've used it quite successfully for transmitting water from aquariums up and over its top edge, as its flexibility is perfect for such needs.

And if its necessary to install a barbed hose fitting into it, first soften the flexible tube end by placing in water hot enough to soften it, then push the barbed fitting with the proper cement into it in the direction it should be facing quickly, as very soon after making contact with the flex hose it won't move any further! Holding the flex end of the pipe into the steam coming from a teakettle is also a good way of softening the tubing. Keep in mind to cut the end of the flexible tubing as square as possible and insert fully to seat it firmly onto the receiving fitting. Be sure to coat both the fitting and piping with a proper primer and then apply sufficient glue to make the connection. Hold for 30 seconds to be assured of a positive bond and then avoid any pressure on the connection for at least 24 hours.

Furthermore, questions have arisen about the safety and long-term durability of flexible piping, so lets address these here. First, one of the products used to make it flexible is a chemical called a 'plasticizer.' One such product is phthalate (di-ethylhexyl-phthalate: DEHP) and is said to be toxic. In the early 2000 timeframe, Dr. Craig Bingman went on record to say he would not use flexible piping as the plasticizer used in the makeup of the flex pipe would leached out over time. As most aquarists know, flex pipe does get less flexible as time passes, which is due to the loss of these plasticizer compounds. Commonsense would say they then end up in the aquarium water. Nevertheless almost all aquariums undergo water changes, and also utilize filtering agents such as activated carbon/Poly-filters, etc. Consequently, even though the release of this plasticizer is no doubt happening to some minor amount, there are no known negative affects to aquarium animals that I'm aware of. Therefore, I continue to use flexible piping in aquariums. But if still concerned, you may want to use low risk flexible piping such as what is made with polyethylene, polypropylene, or silicone.

There's also clear PVC pipe, however not only more expensive but anywhere light would enter it would be subjected to algae growth. Over time the growth could slow water movement and cleaning any such piping with long handle foxtail brushes would be difficult with any lengths longer than a few feet (1 meter). But there are magnetically held internal brushes that can be guided through the tubing, but not without difficulty and tons of patience!

Vinyl Hose

Fairly often simple equipment such as canister filters come with flexible clear vinyl tubing that makes it easy to connect to the equipment's barbed fittings by simply pushing it onto these type fittings and tightening their supplied collars. Nevertheless, algae growth inside clear tubing is sometimes a situation that occurs sooner or later and in short lengths can be clean with foxtail brushes. Fortunately, some companies have heard complaints about clear tubing and are marketing various forms of their equipment with black tubing, which will mostly resolve internal growths of unwanted algae.

Modular Piping

Articulated pipes and fittings, such as provided by the Loc-Line™ company, are generally referred to as modular piping and are more convenient than PVC pipe for 'some' applications even though somewhat expensive. Each section attaches to another section via a ball and socket arrangement. By inserting a slightly smaller ball-shaped segment into a slightly larger concave-shaped segment, rotation of the two segments is possible. This allows the piping to be bent, angled, and pointed in whatever direction needed, all without any leakage.

If needed, modular piping can be attached to standard PVC fittings with male pipe thread (MPT) connectors. With a wide variety of shaped fittings, modular piping can allow for outflow into the aquarium from various directions not easily attainable with PVC. It is also black and not easily seen in the aquarium.

Plumbing Accessories

There are a wide range of pipe fittings, so lets begin with simplest, hose clamps and go from there.

Hose Clamps

There are two common forms, stainless steel, and plastic. The stainless steel clamps wrap around the hose end and is tighten either with a screw or thumb tab that turns a small gear that rotates through the slotted band of the clamp. These are very good for situations where some water pressure is developed, as the band is wide, providing a more effective way to secure the hose end. Keep in mind there are many different classes of stainless steel, with some containing mixtures of metal that will corrode/rust, therefore these clamps should be checked at least once annually for tightness and/or corrosion.

As for the plastic clamp, they are usually quite narrow and simply wrap around the hose end and are tightened by pushing one end of its 'toothed' inner surface onto the grooved inner surface of the remaining clamp. They are fine for securing tube ends to low-pressure devices, but should be checked twice a year to insure tightness.

Bulkhead Fitting

This type fitting converts a purposely-drilled hole through an aquarium panel into a receptacle for attaching an array of connective possibilities, e.g., connections to pumps/sumps, and water returns/exits and come in various sizes. Keep in mind its size relates to the dimension of the 'pipe' it will connect to, 'not' the size of the hole that will contain the fitting, e.g., to connect 1.0 inch (2.5 cm) pipe to what is called a 1.0 inch bulkhead fitting, a 1.75 inch (4.375 cm) hole will have to be drilled in the panel surface to accommodate the fitting. This is true for all bulkhead fittings, as holes larger than the pipe size will be required.

For those wanting to install such fittings, bear in mind when drilling the hole there needs to be sufficient space to the aquarium edge to accommodate the wide lip and gasket of the fitting, as they extend much further than just the hole itself. And remember, the supplied gasket always goes on the inside of the aquarium. Nevertheless, if the user has misjudged the location of the hole by placing it too close to an aquarium edge, thereby preventing the broad lip of the inside half of the fitting from laying flat on the aquarium surface, the inside fitting portion could be, if feasible, placed on the outside of the panel. If so, then both portions of the fitting should have a gasket under it. And do not over tighten the bulkhead-tightening ring; as it's the purpose of the gasket to prevent leaks, therefore apply just enough pressure to form a snug fit.

Fitting size selection depends much upon the goal of the aquarium, as some require greater water flow/higher pressure water pumps than others. Keep in mind there are several location possibilities - the two most popular have fittings at the water level for removing/returning water, or inserted into the bottom of the aquarium that in turn contains an inserted overflow standpipe. In such uses, a 1 inch (2.5 cm) fitting can handle approximately 120 - 250 GPH, with a 1.5 inch (3.75) fitting handling about twice that amount. Of course, there are many factors, such as length of piping in the system, number of turns and twists in said piping, and pump location and its head capacity that make it difficult to precisely judge bulkhead size.

There may also be situations when more than one bulkhead fitting is needed to adequately distribute water back to the aquarium. This would of course affect fitting size, as two .75 inch (1.875 cm) fittings can now deliver the same flow as a single 1 inch fitting. Yet one must keep in mind their location in the piping system somewhat dictates the pressure/force of the water that will exit them, as the one closer to or in line with the pump will have the strongest outflow. With that said I've found in these cases it's wise to use outflow bulkhead fittings somewhat larger than thought adequate. That's because the stronger of the outflows can have a ball-valve inserted into its piping that can slightly reduce its outflow force, thereby increasing flow pressure to the other outflow fitting, then possibly equalizing outflow to both. Keep in mind outflow bulkheads too small will apply backpressure to the delivery pump and possibly place undue pressure on other fittings throughout the piping system. Furthermore, too small outflow bulkheads may prevent return water from adequately leaving the aquarium causing it to overflow - wet carpet time!

It should go without saying, but once system flow rate is finalized it is wise to accomplish some research into what size outflow and inflow bulkhead fittings will be needed if you're doing the installation yourself (that's before cutting any holes!). In fact, you may want to look at ready-made similar sized aquariums systems as to what size bulkhead fittings/flow rates they provide, or at least research the subject matter on the Internet.

Other PVC Fittings

There are many differently shaped fittings that can provide endless possibilities for configuring one's aquarium piping system. Each has a purpose, some are quite useful and some that seem useful have drawbacks that I've personally experienced. But before beginning, keep in mind the more direct the flow from the main pump, i.e., the less fittings in the piping system the more volume and pressure will be its outflow. Lets briefly describe some of the more widely used fittings, their general purpose along with some usage comments.


These are similar to couplings in that they allow pipe sections to be joined, and/or connect pipe to equipment such as pumps and protein skimmers. They come in two forms; male and female. The male fitting has a slip opening on one end and a male threaded end on the other, while the female fittings have an internal slip end and a threaded end. They come in various sizes and also reducer forms that allow items of different ID to be joined, such as pumps to much larger ID pipe.

Barb Fittings

These fittings are designed for connecting vinyl hose sections together or vinyl hose to other forms of PVC fittings. They come in various sizes and types, e.g., barb to barb, barb to female, or having male threaded ends. Generally, where the barbed end is pushed into the vinyl tubing a hose clamp should be used to keep it firmly in place.

Caps and Plugs

As the name implies, caps or plug fittings are used to either temporarily or permanently seal/close a pipe opening or a port opening on various types of equipment. There are various sizes in both thread and slip configurations.


These fittings simply connect two sections of pipe together and are handy if a pipe length was misjudged or a portion of the piping system needs to be re-piped. They come in various sizes, even reducer versions, and slip to slip, thread to thread, or thread to slip configurations are avialble. Very handy when a piping change needs to made.


These fittings when installed in piping provide an angled, usually 45 or 90º change of direction for water flow. They also come in various sizes with slip to slip, thread to thread, or thread to slip configurations. Some 90º elbows, called 'street ells,' have a thread or slip end with the other end having a spigot (SPIG) or male pipe thread (MPT). There are also 'reducing' elbows that can downsize the connecting piping. But keep in mind, their location should never be near the outlet of high-pressure pumps as backpressure will develop and negatively affect the pumps capability and lifespan. And do not make the mistake that two 45º elbows would have less resistance than one 90º elbow as that is not true.

Reducers Bushings

These reducing bushings can be used to slip or screw into other fittings and reduce their size. They are quite handy if it becomes necessary to downsize a large diameter pipe or outlet to something smaller.


These fittings allow for the pipe flow to branch-off into a 90º direction, and the name 'Tee' fits them to a 'T.' I just couldn't resist that! They come in many different sizes, some having all slip or threaded connections, or with the main connection threaded and the branched opening a slip configuration. There are also reducing tees, with the main branch reduced, i.e., less ID than the branching 90º outlet.

Sometimes these are used to divide return water flow from a pump so as to provide outlets at each end of the aquarium. In some situations, aquarists placed the tee, possibly near the top of the aquarium, and run a length from each branch to opposite ends of the aquarium. However, without a means of controlling the flow from either of the opposite branching streams, water flow will be unevenly delivered to these outlets. Therefore, a valve needs to be inserted somewhere along each opposing branching pipe to regulate its outflow. Furthermore, tees should not be installed directly into the outlet side of a high-pressure water pump, as it causes backpressure on the pump.


These are a two-piece fitting that separates by unscrewing one half's tightening collar from the other half's threaded surface, and contain an internal O-ring that prevents leakage. They come in various sizes and thread to thread, slip to slip, or thread to slip configurations. These are often used on the in and/or outflow connections of major equipment such as high pressure water pumps or where sections of piping might have to be removed for periodic maintenance, such as the cleaning of a large perforated spray bar. As functional as these may be, it was always necessary to install a shutoff of some type (ball valve/gate valve) in the piping near the union to prevent water still in the system piping from draining - possibly onto the floor! There are now union/ball valve combined units called 'tru-unions' that resolve this having to use two separate fittings, and they should be considered for the purpose of isolating said equipment.

Keep in mind if located on the intake side of a pressure pump, they should remain full open while the pump is running, as any restriction to the flow entering the pump negatively affects pump lifespan. In fact, if the pump needs removing, shut it down first, and then close the ball valves on both sides for pump removal. Be prepared for some water loss, as a small amount will remain between the valves and pump.


When it comes to 'controlling' the amount of flow through piping there are basically three choices, gate, ball, and check valves. I've used all three and have thoughts as to which I would no longer again select and why.

Ball Valve

These valves have an internal central half-ball shaped structure that can be rotated with its external handle that allows for anything from completely shutting off the through flow to allowing full flow. There are many different models, some with separate union fittings (tru-union ball valves as noted above) that allow for equipment located between them to easily be removed with little system water loss. Their elongated handle is an indicator as to flow direction. If inline with the piping, flow is fully allowed, if perpendicular to the piping, flow is shutoff, and in between positions regulate flow as desired. There are also three-way ball valves that can allow division of water flow from one pipe to another connecting pipe. For the purpose of isolating equipment, tru-union ball valves are the best choice. One further thought, you get what you pay for as inexpensive valves have questionable quality, and if they leak or the handle malfunctions the entire flow needs to be shutdown and the piping drained to change them.

Check Valve

These are used to allow flow in only one direction and have personally found that overtime sentiment, calcareous worms, and other obstructions keep their flapper or ball from fully closing. Nevertheless where system pump is above the water supply, a check valve on the inlet side during a power outage might keep enough water in the pump to keep it in a primed condition for an automatic restart when power is restored. They all have an embossed arrow showing flow direction and if possible should be installed so the connection to the flapper or ball is top wise/in a vertical position, as gravity then helps somewhat with the closing of the valve. Otherwise they have limited uses in aquarium systems.

Gate Valve

Having a similar purpose as to that of the ball valve, gates utilize a circular handle that is rotated in one direction or the other to move an internal vertical sliding door upwards or down to regulate water flow. They provide for more precise water flow control then do ball valves, however, because of the upward path of the sliding door and its handle, their overall height is far greater than a ball valve. Nevertheless, where precise water flow requirements are needed, such as in some large protein skimmers, they are far better than ball valves. And again, buy a well-known brand, as I've had inexpensive gate valves where the internal gearing stripped and left me with no choice but to shut down, drain the piping and install a quality brand valve. And one further thought, I've found gates somewhat better than ball valves when it comes to a positive shutoff as ball valves sometimes have calcareous worms growing on their ball surface that can prevent a 'positive' shutoff whereas the gate's door slides in a narrow channel that cleans out small obstructions and provides a positive shutoff.

Substrates/Live Sand

There are very few aquariums that do not use some form of granular material to cover its bottom areas, with that material generally called substrate/sand, or live sand, i.e., that already containing various species of live/dormant bacteria that quickly provides for additional biological filtration to supplement that provided by live rock.

Even though dry/dead sands may be purchased less expensively, as they contain no living organisms and will take many weeks to become fully biologically active/colonized, live sand is only somewhat more expensive and helps to quickly, a few days in some cases, establish the necessary cycle of biological aspects necessary to support life in the aquarium.

There are numerous forms and will not cover materials such as epoxy-coated gravel or colorful glass/marble chips, as they are better suited for some freshwater aquariums. As to what type materials are most often used in marine aquaria, those will be described here. And even though subjects such as grain size and depth of 'sand' beds will be discussed in the next 'Section' it will be chatted about here since it can serve as a 'preface' to that 'filtration' discussion.

As for my thoughts on these subjects, lets divide this area of interest into four subtopics; Substrate Materials; Grain Size; Bed Depths; and, Sand Sifters.

Substrate Materials

Keep in mind where marine aquariums are concerned, especially reef aquariums where some corals require calcium for growth, calcareous materials (containing calcium) are better suited; nevertheless, other types of material such as silica sand are occasionally used. Of the many types of material, those containing aragonite are the most soluble, so lets begin with it.


This form of substrate is fairly rare and found mostly in areas where, geological speaking, there were recent deposits of tropical marine sediments/sea creatures. It's an easily dissolved form of calcium carbonate as it begins to dissolve at a pH of 8.2, making it a highly suitable material in reef aquaria where mineral demands are higher than in fish-only aquariums. Most other forms of calcium carbonate only begin to dissolve when pH is approximately 7.8 or below.

Additionally, orthophosphate coatings do not affect its dissolution, while other forms of calcareous material are impacted. This may be a reason why it provides a more stable pH and enhanced growth rate for stony corals and clams when compared to other forms of calcium carbonate material.

Aragonite is also somewhat unique in that it's without associated unwanted elements such as silica/quartz or the high amount of dead organic material often found with some beach-collected material. It comes in different grain sizes from a very fine size (below 1.0 mm) to much larger depending upon the purpose of the product/its intended use. It slowly releases calcium, magnesium, strontium, iron and other useful elements helping to maintain natural calcium level, sustain alkalinity, and reduce the need for some additives. It's also highly porous and angular shaped with rough surface areas allowing for good bacteria adhesion and diffusion. This material is always my first choice when feasible/available.

Crushed Coral

My second substrate choice is crushed coral and one must carefully select this product as different materials called crushed coral are available. It should be first said; this product is not made up of crushed pieces of broken coral skeletons. It's mostly crushed limestone from ancient reef areas and depending upon their location can either be mostly aragonite or calcite. The material mostly coming from various mainland USA areas is basically a calcite product having a solubility in the pH range of 7.2 – 7.6. The product generally coming from the Caribbean is mostly aragonite making it more suitable for reef aquaria as it begins to dissolve at a pH of 8.2.

This 'mined' material is crushed and graded to a grain size useful for marine aquariums, e.g., 2 - 6 mm and its physical grain structure is very porous with sharp irregular edges providing very good attachment sites for bacteria. Sometimes shell material finds its way into some mixes and since some shell material contains considerable amounts of phosphate and heavy metals its advisable to select brands that are shell free.

Oyster Shell/Crushed Shell

As with crushed coral there are choices. Crushed oyster shell, mostly calcite, is just that and is sold both at feed stores as chicken feed and in some pet shops as substrate for marine aquariums. It usually contains a lot of calcareous dust and therefore requires a thorough washing before use. Even though two or three washings may fail to remove all the milky white calcareous dust attached to the shell particles, it's safe to use. However this material is 'flat' pieces of shell and may pack tightly over a period of time thereby restricting diffusion. Additionally oyster shell pieces have smooth surfaces making it difficult for bacteria to adhere, and the larger the particle the less total surface area in a given volume of particles when compared to small sand grains for bacteria to adhere to.

Nevertheless other type shell material, such as Puka shell, favor aragonite in their structure and would be far more suitable for substrate use in marine aquaria. So there are choices as to shell material, yet keep in mind particle size and their shape as these aspects affect diffusion and bacteria sites. Also of importance some shelled animals are algae grazers, and if so, the shell material may contain phosphate and heavy metals.

Oolitic Sand

'Oolitic' is a term used to describe the shape/structure of this particular sand grain, which consists of concentric layers (like an onion) of calcium carbonate that surround tiny remains of coral skeleton, invertebrate shell, calcareous Halimeda algae and varying amounts of calcite. It's shaped differently than the more pure aragonite products as this chemical precipitate of seawater occurs when cold calcium rich waters get carried into shallow warm tropical seas and is mostly round. Furthermore, even though most oolitic sands contain aragonite, the land mined products from southern Florida, i.e., Miami Limestone or Key Largo Limestone, have a far greater percentage of calcite and considerably less strontium than do its Bahamian Bank counterpart making the Bahaman Banks products more desirable for reef aquaria. Even though it's technically correct to call all these products an 'oolitic aragonite sand,' products that are largely aragonite, i.e., having a far greater percentage of aragonite, render far more buffering. Nevertheless because of its smooth rounded shape, sites for bacteria adhesion are not as good as they are with courser-grained material.


This is another form of calcium carbonate, somewhat softer than dolomite, yet not much. It begins to dissolve between a pH of 7.2 to 7.6 (metastable range) and can be considered a very suitable substrate for undergravel filter systems, yet of little value where some calcium buffering would be helpful. Calcite products, generally mined and crushed limestone from ancient reef deposits (see crushed coral above), are ineffective buffers in marine aquariums.


This commonly mined calcium, magnesium, and carbonate-based mineral is less soluble than calcite or some crushed shell products and provides far less buffering, if any, than other forms of material. Large deposits of this mineral are crushed, washed and screened and sold as garden/lawn decorations and/or substrate for some types of freshwater and marine systems. Their highly rough surfaced particles work well for bacteria adhesion and also space well because of their angularity, thereby allowing for good water flow. Since Dolomite has little or no solvency in the marine aquarium, yet has excellent attachment sites for bacteria, it's an excellent substrate for UGF systems. It should be washed well to remove any dust-like material that coats or accompanies the material as it can be high in trace amounts of aluminum, arsenic, lead, and/or mercury. The dolomite particle has a metastable range of the high 6 to low 7 range.

There are a few other sands readily available; a very common beach or lagoon collected sand, an industrial sand, and the common, non-calcareous silica sand.

Coral Sand

Coral sand is usually a calcareous material naturally occurring along the beach or in lagoons. It's generally produced through wave action breaking over old coral skeleton material or the rolling motion of coral pieces in turbulent areas, which slowly reduce it to sand particles of various sizes. Parrotfish, which feed on stony corals for their zooxanthellae by grinding their beak-like teeth on their surfaces, also produce the sand. It may consist of aragonite or calcite, sometimes both. Its particles are often smooth sided and small, about 1 mm, thereby somewhat reducing bacteria adhesion sites. It is wise to know where it's collected because if its 'beach' collected it may contain an inordinate amount of organic material as human wastes and petroleum from ships and natural seepage may find its way onto this medium. Depending upon its origin, grain size varies, as does its color and always purchase this type sand from a highly regarded company.

Industrial Sands

These calcareous sands' are generally used for abrasive purposes, such as in the glass making/painting industry and are often sold off when their exterior grain surfaces lose their abrasiveness. One should keep in mind when products such as these are originally selected and used by these companies; their original contaminations or those creeping in while being utilized are not of concern. Therefore use of this type product in aquaria as a calcareous substrate should be evaluated carefully before using it. Furthermore its particle surface has now been smoothed, thereby greatly reducing attachment sites for bacteria.

Silica Sand

This non-calcareous construction material is usually sold by home improvement or lumberyards in many different particle sizes, such as a #20, 40, and 60. The Number 60 is what might be seen in cigarette urns. This 'very' fine silica sand is easily moved about by water currents or aquaria animals and can easily end up deposited on your live rock or corals. Been there, done that, and had those results with my aquarium looking as if a snowstorm just passed through it! Number 40 is also too small and can also be easily shifted about by fish or water currents. This leaves number 20, which has a particle size of about .85 mm. Size 40 is about .42 mm, and size 60 is about .25 mm.

Size 20 appears to be the best of the three commonly found sizes as it mostly stays in place even where there are fairly swift current flows. Nevertheless, still consider it too small for efficient biological processes. There's also a product called 'Playsand' that is mostly used in children play areas, and is also a silica sand based product, yet much cleaner than the construction grades.

There are both positive and negative aspects associated with its use. When phosphate precipitation occurs, it will not adhere to the silica particle as calcium phosphate (apatite) as it does on a calcareous material. Depending upon the aquarium environment and bioload that could be viewed as either a positive or negative aspect. Also on the positive side, its very 'white' color renders a pretty, natural looking 'lagoon-like' bottom. Probably the most negative aspect is there is some minor dissolution with the product in alkaline water above a pH of 8.0. And the rate of dissolution increases when pH reaches 8.5 and because of that, brown diatom algae can be greatly encouraged. Because it can cause diatom algae, does not buffer water as does a calcareous material, and its particles are smooth sided, it has limited use in marine aquaria in my opinion.

Grain Size

Powder-like particles to pieces quite large, e.g., about a quarter inch or larger are readily available and obtainable in different substances, such as aragonite, shell particles, calcite, etc. Nevertheless, its grain physical size and shape that will impact the bacteria wanting to colonize its surfaces.

As for fine sand grains, i.e., below 2 mm, it has been thought that the more grains there is in a given area the more bacteria there would be living on them, resulting in improved filtration processes. Not exactly correct! Because very small grains pack together very tightly there is less space between them, technically called void space, and when this happens oxygen diffusion into/through the bed is restricted thereby reducing the volume of the areas where more valuable biological processes occur, e.g., mineralization, nitrification and 'destructive' denitrification. And at the same time, increasing the area where Ammonification, a form of denitrification that only reduces nitrate back to ammonium, occurs. Basically it's more bacteria but not the right volume of the right 'class' of bacterium. However, if the keeping of rays or other forms of burrowing fish are involved, a deep fine grain sand is the perfect base material for these animals.

If grain size were too large, e.g., 6 mm or above, it would allow oxygen to penetrate much deeper, thus inhibiting denitrification by extending the depth of upper oxic/oxygen rich zones. Detritus penetration is also quite feasible and if this occurs due to poor maintenance, oxygen penetration can be reduced if it collects and would then result in the development of a microenvironment that produces its own needs and shunts the essential diffusion that would normally produce useful denitrification in the bed. A probable scenario would be single cell alga and diatoms colonizing it first with more complex multi-cellular algae and structured algal mats soon to follow. Nevertheless, if a nutrient rich environment is desired, the use of large grains can help further that goal.

To sum it up, rough surfaced calcareous grains that would provide both good adhesion sites for bacteria and calcium dissolution along with other useful elements helping to reduce the need for some additives, such as aragonite is my top choice. As to grain size, it depends upon the goal of the system as very fine grains, i.e., below 2 mm provide a physical size that will not injure fish that prefer to burrow. Yet where balanced biological processes are desired, as in some natural reef systems, the 2 - 5 mm size is a better choice in my opinion as it provides for better diffusion, possibly leading to a more microbial efficient bed.

Bed Depths

The purpose of the bed is twofold; that of providing a natural looking 'lagoon-like' bottom area, and, an area of biological filtration. The two most popular bed depths are the shallow bed, i.e., 1 - 2 inches (2.5 - 5 cm) or the deep bed, approximately 4 inches (10 cm) or far deeper. Either can be successful, yet some aquarists considered one far more microbial efficient than the other. And since grain size and depth directly relate to efficiency, it's beneficial to understand what can be expected when these two aspects are taken into consideration.

As for a shallow sandbed, I recommend its depth be no deeper than 2 inches (5 cm) utilizing a course grain size in the range of 2 - 5 mm. These size grains tend not to pack down (better void space) as does finer sand, which would subsequently reduce biological efficiency and balance. In fact, these grain sizes actually allow for optimum oxygen penetration/diffusion throughout most of this recommended depth. Moreover this recommended grain size is still small enough to prevent most detritus from finding its way down into the bed and accumulating. Detritus will tend to stay on its surface and can easily be siphoned/vacuumed out of the aquarium or used by surface detritus grazers. And I should add the shallow bed is by far the bed depth of choice among most aquarists from what I've seen in my travels.

Where deep beds are concerned, i.e., those exceeding a few inches, the goals there have varied. I've seen deep beds used in refugia where the desire was to maintain a more nutrient rich environment to encourage lush algae growth, thereby utilizing the refugium as an algae filter. And to further enrich that area in some instances, very fine sand or mud particles were used. If this is the goal, then a deep bed with a fine substrate is the way to go. I've also seen deep beds used where the aquarists' were keeping sharks and/or rays, or maintained various types of burrowing fish. And most contained fine sand in the range of 1 - 3 mm which would not injure the animals when contacting it.

In complex reef systems, it's my opinion a deep bed is counterproductive when it comes to maintaining a nutrient poor environment for the long term. Many years ago some thought that if there were more sand grains there would be more biological activity as there would be more bacteria, therefore the aquariums 'environment' would benefit. Its true the numbers of 'bacteria' is far greater, yet that's simply because there are more grains of sand to inhabit. Unfortunately the more valuable 'classes' of bacterium that actually contribute to better water quality cannot exist at depths much below about 1 inch (2.5 cm) depending upon grain size because the diffusion of oxygen needed to carry out their processes is lacking. Therefore, in deep beds the majority of the biological processes do not contribute to a more 'overall' balanced environment and this aspect will be discussed in length in the next section so its fully understood.

Nevertheless, at this point it's important to remember that in most cases, critical and dominant biological processes are mainly occurring only in the upper 1 inch of the bed. Below that, a less efficient form of biological filtration is occurring. Therefore, limiting that area/volume of less efficiency often makes much sense! Keep in mind that less efficient forms of biological filtration can easily become prevalent, and when this occurs, one of its results is a favorable environment for unwanted growths of algae. If the favorite color is green it might be acceptable, such as in environments where macroalgae is favored. A deep bed could appear successful for a long time; yet, depending upon aquarium bio-load, on-going maintenance and what associated high tech equipment may be in use it may become a disappointment somewhere down the line.

There also appears to be some thought that deep sandbeds are great for supplementing calcium levels. The more sand, the more area of lower pH in its depths, therefore, the possibility of some additional grain dissolution. Not totally accurate! As for 'some' additional calcium ions, there may be some small increases with deeper sandbeds than there is with shallow beds. Nevertheless, it's not worth skewing the microbial balance of the system to gain what can be considered a marginal amount of calcium ions. It's like one minor step forward with the natural additional of a very small amount of calcium, but two big steps backward with additional plant nutrients, as deep beds encourage a form of less efficient denitrification (Ammonification).

Yet, depending upon the goal of the environment/aquarium, deep beds can provide certain animals the base they need to feel comfortable in, such as with rays, and some gobies and wrasses for example. As for general bed maintenance, see Chapter 13.

Sand Sifters

Some aquarists seem to think there is a need for numerous animals called sand sifters, e.g., hermit crabs, brittle stars, some types of seastars and cucumbers. Even though these somewhat small invertebrates are mostly very efficient at manicuring the upper sandbed surface, there sometimes seems to be a misplaced emphasis on the quantity needed.

If too many sifters are used, their digging in the sandbed may increase its dissolved oxygen content. That might change low oxygen bed areas to more oxygen rich conditions if dug too deeply. If that occurs, it could result in a change to the bacterium classes that occupy the disturbed areas and lead to its reduced microbial efficiency. Also, certain sand sifters, e.g., some gobies and crabs, can actually dig large holes, further oxygenating lower surrounding sand areas.

Keep in mind sand sifting invertebrates are also a major source of DIN (Dissolved Inorganic Nitrogen) and DON (Dissolved Organic Nitrogen) as well as DIP (Dissolved Inorganic Phosphorus) and DOP (Dissolved Organic Phosphorus) as they are supplying poop of their own in forms more available to primary producers like algae. The implication here is that algal problems could be favored more than discouraged.

As to 'Sand Sifting' starfish/seastars, e.g., Archaster typicus, it has in my aquariums turned over the upper levels of the sand and plow through the bed, wiping out the valuable inverts in the sand! Never again would I have this species in my aquariums! Yet hermit crabs, such as Clibanarius tricolor are real assets!

Bottom line, use common sense and limit the types and numbers of these sifters. If detritus control in hard to reach areas is needed, use brittle stars. Keep in mind that periodical vacuuming of the upper .5 to 1 inch of sand in the areas where detritus usually collects is a more correct approach in the general maintenance of any type sandbed surface.

Live Rock

Another form of material few reef aquariums cannot go without is referred to as 'Live Rock.' Its selection, processing, and placement are of utmost importance, and in fact can be the difference between overall success and failure. As to what is 'live' rock, what types of rock is available, how much to purchase, how to prepare it for use, and the best ways to place it in the aquarium, all will be discussed below.

When other than the experienced hobbyist hears the term 'live rock' we wonder what they must be thinking! Explaining what a live rock is, especially to those unfamiliar with the hobby, can certainly bring some odd responses. About thirty years ago while at a local aquarium show, one of the most popular aquariums was a large reef aquarium complete with various corals, fishes, macroalgae and live rock. I would guess about 50,000 people viewed this show at a local mall, but only one percent, if that many had the faintest idea of what live rock was.

Part of my tasks at the show was to explain and/or answer questions pertaining to a large reef aquarium. As I went through my routine about the necessary equipment and what animals were in the aquarium, it would be difficult to explain the looks received from small children to senior citizens when I mentioned the term 'live rock!' Besides funny looks, there were some great comments and I decided to write them down as I thought readers of a magazine (Marine Fish Monthly) I was writing for in those days might enjoy some of the more interesting and printable ones.

They were: do I look stupid or something; your kidding; a live ROCK, Ha Ha Ha; what do you take me for; are these something like those little crystals that you put in water and watch grow; your full of it; I'm old but not dead; really; where do they come from; and the best one was "how big do they get!" So you can see that newcomers to this hobby were not alone as to the term!

With the price of quality live rock still on the rise today, the least expensive way to go in the long run is to be very well informed before the purchase and get what is the right type of rock the first time. As for price, I can remember when the best live rock was a couple of dollars a pound. Of course, I can remember when sneakers were two dollars a pair! With quality live rock prices increasing and sneakers about 80 – 100+ dollars a pair, you may soon need a loan before you buy your next shipment of live rock (or sneakers).

As for live rock, it's sometimes storm caused broken pieces of the natural reef structure, or old reefs harvested by collectors. There's also sedimentary/concrete-like accumulation of shells, calcareous algae, sand, and coral rubble. All are sort after by collectors and shipped worldwide. Most natural live rock is somewhat porous, lightweight and basically a calcareous material. Various crustaceans, algae and helpful bacteria may inhabit them, hence the name 'live' rock. For those of us fortunate enough to live near the ocean we may be able to collect our own live rock if still legal in that area. Otherwise it becomes necessary to purchase what is needed at the local retailer, which is my preferred method since you have an opportunity to make sure it's 'exactly' what you need.

If the local dealer cannot supply it, there are now many websites that offer live rock, so checkout photos of the rock if possible before buying. If what is purchased does not resemble what was in the photograph, some of the better web companies will offer a credit. If treatment is unfair, post your dissatisfaction in a professional manner on any of the many hobbyist webpages. Send a copy to the product company so they know unfair practices will hurt their business. Again, all I ask is that it's done in a fair and professional manner. That way, everyone is better served.


One of the first questions asked by those new to the hobby is why use 'live rock.' Well, there are many benefits to be gained that experience has shown enhance the aquarium's chance for long-term success, whether that is a fish-only or reef aquarium. Let's take a look at those benefits:

  • Natural Environment Appearance - Live rock not only makes the aquarium environment look more natural, it can also be very interesting to watch the various small life forms living on and in it. It can also be considered the foundation and support for the finishing touches such as the coral animals that will/may decorate its surfaces. Those of us who utilized live rock have come to realize that fish in aquariums containing live rock also remain healthier than those in aquariums filled with bleached coral decorations. That's because they feel more comfortable in their surroundings and are more apt to maintain a healthy slime coat that can ward off parasites. Simply put, a happy fish is a healthier fish, similar in some ways to that of humans.
  • Filtration Benefits - Each rock contains various life forms that acts like a functional biofilter that aids in the biological breakdown of unwanted elements and compounds entering the aquarium from the wastes of the animals and/or the excesses of foods, e.g., bacteria living on and in the rock (aerobic and anaerobic) perform mineralization, nitrifying and denitrifying processes, and worms and crustaceans that often inhabit the rock can find their way into the aquarium bottom substrate providing for natural processing of detritus. Simply put, it is a natural biological filter.
  • Natural Food Source – Often, small crustaceans live inside or on these rocks and once established in the aquarium these isopods, amphipods, copepods, chitons/snails, worms, etc., can help reduce undesirable algae films and/or in turn possibly provide a very valuable food source for fishes and other larger invertebrate. In some cases, feeding the system prepared foods can be reduced, resulting in a lower accumulation of unwanted organic pollutants. The ultimate result is healthier fishes and invertebrates and less problems with unwanted algae growths.
  • Buffering Capability - Most live rock is composed of a calcareous material. Its porous interior usually has a slightly lower pH than its outer surfaces and this helps to dissolve a small amount of its interior calcium and magnesium carbonate structure, possibly providing some additional 'buffering' to help maintain aquarium alkalinity.

Because of these benefits, live rock and its micro and macroorganisms should be considered an integral part of the marine system, whether that's a fish-only or reef aquarium. In fact, I see the use of live rock as the foundation of many marine aquarium environments!


As for the selection process, the question most frequently asked is how many pounds of live rock is needed in the reef aquarium. The standard answer has been about two pounds (1 kg) of rock per gallon (4 L). Yet, depending upon your aquascaping ability and type of rock selected, it can be done with a lot less. Of course, that really depends on the weight and structure of the rock, which in turn depends upon its origin, e.g., Florida, Caribbean, Gulf of Mexico, Marshall Islands, Tonga, Fiji, Bali, and lately, from Central America. In fact, my previous 125-gallon Jaubert/NNR reef aquarium was completely aquascaped with only 65 pounds of branching rock from the Marshall Islands.

As for live rock from Florida, it's an excellent cultured grade of calcareous rock, usually more solid/lumpy looking in general structure/heavier than rock collected from mid-Pacific areas. Tonga and Fiji rock is also excellent calcareous rock, yet more gnarled in shape and fairly porous in structure. The Marshall Island rock, when and where still available, is mostly old Acropora skeleton material, tubular or branch-like in shape and firm calcium carbonate material. Because of its tubular shape, less poundage is required to setup a reef aquarium. Yet, it is one of the more expensive forms of rock, however, very advantageous because its open structure allows for better water flow in the aquarium. Supply of this rock is already growing very short.

Retailers have often provided more than one type live rock, however, names applied to those selections added some confusion, especially in past years. There were, and still are in some countries, names like fresh/rubble rock, algae or plant rock, seeded rock, cured rock, base rock, unseeded rock, cultured rock, branching rock, and calcareous rock to name some that I've seen. Some rocks simply have the area/island it comes from as its name. And even though some of these names no longer seem to exist in middle and north America, I've received email seeing some of their names from several far east countries, so lets look at possibly some of the more valid ones and what they 'may' consist of:

Fresh/Rubble Rock

This may be any type rock from any area that is not first cleaned or processed before shipment to the dealer or to you directly. It's sometimes referred to as base rock, uncured or unseeded rock, and is usually the least expensive types of live rock. It can be the most dangerous rock to take out of the box and put directly into the aquarium. Rock that is not properly cleaned may be high in dead organic matter, very low in beneficial bacteria, and contain unwanted crabs and mantis shrimp along with different forms of unwanted algae, e.g., Valonia (Bubble Algae), and/or Derbesia (Hair Algae).

This type rock may have also been collected in near-by shore areas that are usually high in nutrients. They were probably stored dry before shipment and not scrubbed clean of unwanted algae or external sponges. Much of this sedimentary/limestone rock and/or rubble may be porous because of a boring sponge called Cliona. This sponge lives inside the rock, happily tunneling through its interior. Unfortunately, if the rock is out of water too long the sponge dies and fouls internal pathways. Placing this type rock in the aquarium directly out of the box is like begging for a hair algae problem and/or gray hair! If this is all you can afford, then you need to take the time to carefully process it before placing it in the aquarium.

Plant Rock

Collected in shallow nutrient rich water and covered with different types of macroalgae, usually Caulerpa, and sometimes simply called Algae Rock. Halimeda, often called the Money Plant because its calcified segments are generally round like coins, is also sometimes found on so-called plant rock. That shown in the photo was being sold in a LFS as 'Plant Rock,' and actually was a nice specimen of Turtle Grass, Chaetomorpha aerea. Generally, when and if available, quality specimens may be useful in refugiums or aquariums desiring a 'quality' type algae growth.

Calcareous Rock

Sometimes referred to as fossil rock, it's usually a sedimentary accumulation of shells, calcareous algae, sand, and coral rubble, and its forms/shapes vary as to area of collection. Suggest caution when buying this type rock if it comes from the Gulf of Mexico, as it may be partly composed of silica sand that can possibly generate long term unwanted brown diatom algae problems in the aquarium. Presently, its now rarely seen in the trade.

Base Rock

This is usually a low price rock that is lacking plants or invertebrate of interest. Rarely comes with any encrusting coralline algae. Depending on where it originates it can be anything from fairly good to absolutely worthless. Sometimes, because of its usually large size, it's used as the 'building blocks/foundation' for all those soon to be added special pieces of rock/live corals and/or other forms of special items of interest.

It really should be cured before placing in the aquarium. In plain words, it is gathered, stored, and shipped with the least possible effort and at the lowest possible cost. Therefore the survival of any possible worthwhile organisms is just about nil, so exercise a lot of caution before utilizing this type rock.

Branching Rock

These are sometimes broken pieces of Staghorn or Elkhorn coming from the Caribbean or broken pieces of Acropora or Pocillopora coming out of Indo-Pacific areas that were the result of storm damage. This is quite dense rock, with smooth surfaces and almost always free of embedded boring sponges, crabs, and unwanted other pests. If freshly collected and available, it can be found encrusted with some coralline algae depending upon when and where collected. Branch-like lengths over 24 inches (60 cm) can sometimes be attained, which make for very nice material to construct open bridge-like structures in the aquarium. That shown in the photo, even though needing some cleaning, would be my first choice over that of many other forms of live rock.

Cured Rock

This is rock the collector has made an additional effort from the time of collection to the time of shipment to keep wet, possibly aerated and scrubbed clean of unwanted algae and/or sponges. Some collectors that ship direct to the hobbyist may keep cleaned rock in a holding tank for several days allowing for unwanted nutrients to leach out. Rock is then usually shipped covered with wet newspaper, but not submerged in water so as to save shipping costs. Some of the better local dealers also inspect and clean this rock as necessary and store it in well-aerated tanks before selling.

Seeded Rock

This term was used a long time back to describe 'cured' live rock that may have been given additional time after initial collection and cleaning so as to allow bacteria to re-colonize (seed) its surface and interior areas. Some dealers liked the term, some did not. Today, Fiji rock and other similar rock simply fall into whatever category dealers prefer to call it. Yet, it should be looked at as if this rock has had the time and effort applied to it so as to render a quality live rock that is fairly nutrient free and ready for use in the aquarium. In fact, if the hobbyist needs to take rock from the shipping container and place it directly in the aquarium, purchasing branching or cured/seeded live rock is the best way to go.

Cultured Rock

This type rock is often available from Florida waters, and if sometimes simply called 'Aquacultured' rock. It's generally composed of local dry aragonite rocks and sometimes old Bahamian coral rubble. These dry rocks are then carried to sea on small ships or barges and placed on leased seabottom areas approximately 50 to 100 feet deep. Within six to twelve months various invertebrates and coralline algae colonize them. These rocks are usually lumpy-looking and quite heavy, yet often overflowing with colorful plant life, encrusting sponges, tunicates, and bryozoans. Currently quite available and an excellent product.

Artificial Rock

There are many suppliers of this type product, usually a dry product made from various materials and differently shaped, sized, and colored. Depending upon your goals, some are already designed to look like a reef wall having various artificial corals embedded into its structure, and can be had in different heights and lengths. Recommend searching the Internet if this will fit your needs.

Yet, for those hobbyists wanting to build their own rock based structure, want to mention a new company, Real Reef that I visited with at a MACNA event in Iowa. They are making a man-made product that looked very similar to live rock coming from Fiji, which is one of the more popular live natural rock used in marine aquariums. This artificial, environmentally friendly product is a calcium carbonate based product similar in weight and shape of Fiji rock, and also coralline colored! In fact, it looks like the best Fiji rock money could buy, but is actually manmade! Best of all, its ready for the aquarium as its shipped to local retailers from their grow out tanks and does not contain any unwanted animals or algae! In fact, a local aquarium shop also saw the product at this MACNA and was so impressed they immediately placed a large order for the product. I then purchased enough from them to start a new reef aquarium in late 2011. I found the product excellent, and recommend checking it out if shopping for live rock and comparing it to other artificial rock products!

And as you know from past experience, have a good product and soon others will be producing similar products. As of 2015 other companies have come about producing natural looking reef rock and highly recommend checking the Internet for their also excellent products!


For those do-it-yourselfers it is possible to make your own rock using a mixture of Portland cement and aragonite sand. All it takes is a wheelbarrow, a shovel, tap water, cement, aragonite sand (preferably different sizes), an ice chest or similar container that opens from the top, some inexpensive sand to serve as the mold, imagination and elbow grease! If so inclined, place the topic into your web-based search engine to find a detailed description of the process. Or, checkout the product in the photo, which was seen at the MACNA in Iowa.


Starting a system with a quality grade of rock that has been cured and processed is no doubt far better than beginning with fresh or poorly processed rock. Therefore, it pays off in the long-term to find a reputable dealer selling excellent live rock that has undergone care in its collection, shipment and in their facilities. And if one utilizes a local dealer, it gives the hobbyist an ideal opportunity to get just the right type and shape rock needed for their planned system, and which is usually already well-cured and will not need any special processing care before being placed directly in the aquarium. But the same may not be true when purchasing directly from a collector or through mail order.

If purchasing mail order live rock, what you do with it upon taking it out of its shipping container may be the most important care that rock will ever receive! Even if receiving quality seeded/cured rock, recommend some cycling if possible before it enters the aquarium. Planning ahead and being ready for the shipment before it arrives is, in my opinion, extremely important. And even if the rock comes out of the shipping container smelling ocean fresh there still may be some die-off due to the lack of water and dissolved oxygen during its shipment. It's better putting this organic load; no matter how small it may be, in a separate cycling container than in your aquarium.

As for cycling this type live rock, suggest setting up at least one plastic garbage/trash can half filled (more if needed) with freshly prepared seawater one day before the shipment arrives. Place a large powerhead for circulation in the container(s) and if possible hook up a protein skimmer if available to process its water, as its nutrient load may be excessive.

When the shipment arrives, each rock should be individually inspected for the Chicken Liver Sponge, Chondrilla nucula, which doesn't normally live for very long in closed systems. It's a rubber-like, shiny tan color and often has the shape of stepped-on chewing gum. No kidding, that's what it looks like! When it dies it can quickly add unwanted nutrients to the aquarium. Also look for any unwanted items such as crabs, mantis shrimp, crushed tunicates, small clams, white slime-like growths, and/or any unwanted micro or macroalgae. All this matter should first be removed from the rock before placing it in the cycling container. The cycle time frame varies depending upon type and/or condition of the rock received, but usually five to ten days are sufficient.

The cycling container, (a.k.a. garbage can) should be loosely covered during this time period so as to keep light to a minimum. This may prevent unwanted algae growth during this high nutrient time frame. It's also a good idea to occasionally check the rock to see if any areas of decay have developed, and if there are any rocks with fungus-like growths. If so, remove and clean them. If a particular rock smells like rotten-eggs, that rock may be the 'bad egg' of the lot and is emitting hydrogen sulfide from something decaying inside it. Better to try and save that rock in a separate container than allow the majority of the good rock to incur this toxic compound.

When ready to place the rock in the aquarium, do so quickly without letting too much water drain from each rock. If your aquascaping plan requires drilling or forming the rock into ledges or caves, have all your tools ready for the work at hand. Remove the rock, drill as necessary, and flush the rock/holes by placing it back in the cycling container. When all the pieces are drilled, remove them from the cycling container and form the structure as needed. Place the formed rocks in your half-filled aquarium and continue until the structure is complete. Then finish filling the aquarium and start your filtration equipment. Use a turkey baster to keep the rock clean of any detritus over the next few to ten days, and use a protein skimmer working full time, if possible. During this short time period, leave the lights off and vacuum out any loose material, which helps to keep the organic level as low as possible. If a coralline alga that may have been on some rock dissipates somewhat during this timeframe, it should make a strong comeback when the lights are turned on. This short aquarium 'curing' period will give the very important bacteria and possible worthwhile crustaceans time to get a foothold in the aquarium before consumers are introduced.

Yes, I know most people would like the aquarium fully aquascaped with animals and lighting on the very first day of its existence! But if you have the patience, this additional curing period almost assures an excellent starting environment for the rest of the soon to come additions and a much better chance at long term success. It's said in the beginning of this book that one of the KEYS to success in this hobby is 'patience!'


Lets go back to the opening text in this book where system goals were discussed. What was it you wanted your creation to replicate? Most certainly it was a natural looking environment that replicated the beauty of the area that was to be the focus of your goal. And in that planning stage, which in my opinion is one of the most satisfying timeframes in the process of setting up a new system, it was necessary to devise and/or imagine ways to carryout the construction of that internal environment with the concealment of overflows, returns, powerheads, heaters, ands associated plumbing.

And with that said, the aquariums outer environment should also be given much consideration, as the use of external wires and piping, along with standalone equipment should be limited or hid from view as much as possible. Comfortable seating near the system should also be available, as enjoying one's creation along with sharing the experience with others is what this hobby is all about.

Since there are many different appearing system goals, it would not be possible to discuss each and every aspect of every possible system goal. A better approach is to describe some of the tools or materials that 'may' be needed, and what can be achieved if used properly.


When external wiring or plumbing is seen through and hanging down outside the rear panel, it distracts from all the effort spent on creating an internal artwork that is suppose to duplicate nature. In years past, various sized paper aquatic artwork depicting different colorful scenes was available to attach to the backside of marine or freshwater aquariums. In fact, one of my freshwater plant aquariums decades ago had a paper backdrop of a heavily planted aquarium to help hide some external wiring and filter aids. But over time it deteriorated and became messy, but served a purpose until the system's plants grew large enough to hide most of the rear area. Some of my other freshwater systems had painted backs where I used a paint sold specifically for aquaria backgrounds that left a crinkled look when dry. Could be some reading this book still remember that item!

Today some still use paint and have seen different colors of blue used on some aquarium outside back panels, and in one situation black was used on the outside back and side panels as the aquarium was enclosed in a separate room with only its front appearing like a picture frame in the family room. Nevertheless many marine aquarists utilize rock today to encompass internal pumping or wiring that leads out of the aquarium. But as explained below, that can create untenable maintenance situations in the near future.

The uses of plastic/acrylic panels that are either translucent or opaque are a better choice for backdrops, whether inside or used externally. Externally, they can be taped to the rear outside panel or simply tacked there with some silicone cement and therefore remain removable if so desired. When used inside the aquarium, a long very flexible panel can be bent to encompass both rear corners and in doing so, leave enough room between itself and the actual aquarium corners to house any wiring. Yet not a good place for heaters, as there is no water circulation. Translucent blue panels, whether used inside or outside the aquarium, can be backlit from the outside to give that feeling of visual depth to the aquarium environment. And by positioning different wattage lamps on the aquarium backside, different aspects of depth can be realized from the frontal viewing position.

In fact, internal back panels made from molded sand or dried seashells and stony corals were shown at a past MACNA event that may meet the needs of some aquarists.

Locale and Scale

The size and species relationship of different organisms is another aspect of aquascaping that needs some consideration if one is to successfully replicate a natural appearing environment. If the goal were to replicate a certain area of the wild, e.g., a Caribbean reef, the inclusion of an animal species that solely comes from the Pacific would visually ruin that goal. And no doubt raise some questions from viewers that might be difficult to answer!

Furthermore, size of the organisms or even that of the substrates used to create the illusion of that specific slice of the ocean also need some forethought, as they should truly represent the 'area' in the wild In fact, have seen Acropora species that attain enormous sizes being kept in nano aquariums, and/or juvenile fish that will soon outgrow the aquarium. This not only presents an unrealistic view, it's eventually an unhealthy condition for all its animals.

Therefore, if the goal of the system is to replicate a specific area in the wild, first do some research as to what that area really looks like, i.e., its specific inhabitants, water movement, and lighting intensity. Then relate what has been learned to the size of the aquarium that will contain your similar looking environment and adjust the size and scale of both the animals and substrate that will fill that space and light accordingly. Keep in mind if the aquarium is fairly small its wise to stay with the smaller creatures that naturally inhabit this specific area in the wild. If the aquarium is large enough to accommodate its larger animals, then a broader spectrum of animal life can be replicated. But keep in mind aquarium size dictates the level of replication possible. In fact, I've seen some small aquaria dedicated to the micro-life that naturally inhabits certain areas and they were simply fascinating to say the least!


Backdrops work well for piping and wiring on the rear outside of the tank, but on the inside one of the most utilized materials is rock, whether its live rock from the wild or manmade/artificial. One of the biggest mistakes seen in aquascaping with rock is with improper placement. All to often rock is used as if they were bricks and placed up against side and back panels as if building a brickwall! They are then decorated with various corals coming from an assortment of different areas in the wild and the system as a whole is then called a reef aquarium.

Actually, they should under no circumstances be piled up like bricks against the walls of the aquarium! In such applications long-term maintenance of those areas, i.e., under and in back of, would simply be impossible. Keep in mind the goal is to duplicate nature, not a brick wall, therefore use your imagination. Also keep in mind the use of too much live rock restricts water flow in the aquarium and allows detritus to accumulate in areas that cannot be cleaned. A condition such as that would lead to diminishing water quality and growths of unwanted algae coming sooner rather than later.

For those wanting wall-like enclosures or doughnut-shaped structures, live rock can be drilled and tied together with monofilament line, plastic cable ties, or stainless steel wire to form natural looking wall environments. They can also be stacked safely by drilling a hole through them and inserting a PVC tube to keep them in place and then leaned up against side or back panels allowing for better water flow and maintenance of the sandbed near them. As for using underwater epoxies or cyanoacrylate glues to fasten rock together, have found those methods unreliable, as their bonding capacity often failed.

It's also possible in some designs to place lower level large rocks on pillars/columns of smaller rock, or use branching rock and develop columns connected by bridge-like structures using large sections of branched or drilled and connected rock. And where reef aquariums are the choice, only use enough rock to provide the necessary platform for those soon to be added pieces of coral, which sometimes come on their own live rocks.

And no matter what form your rockwork creations take, leave enough space for maintenance and good water flow around them. Also install multilevel outlets/powerheads at different locations, and possibly time their on-off periods with a wavemaker or simple light timers. This will provide good circulation that in turn may help rid the aquarium of some silt/detritus by carrying it to the overflow or its mechanical filter. It should go without saying, but by placing live rock both functionally and aesthetically, it increases the possibilities for a healthy long-term system.

Some hobbyists raise their rock off the bottom of their aquarium by using elevated shelves of eggcrate or columns of clear acrylic. This helps minimize bottom accumulation of detritus by making it easier to siphon or by flushing the area with strategically located powerheads.

Even though it behooves the reef keeper to utilize 100% live rock for the reasons mentioned above, it is not always economically possible or desired. If faced with budget restrictions, there's dense lava rock such as Tufa/Lace limestone rock and it can usually be used without serious problems. Yet, home lawn-type landscape volcanic rock is not a good choice because it has sharp edges and can easily tear the flesh of fish if they brush against it/ try to dislodge parasites. It may even damage the foot area of anemones and/or can leach harmful chemicals; therefore its a poor choice and should not be used.

Presently, 2015, there are 'dry' limestone/calcium carbonate 'white' forms of so-called lace rock coming from Utah, Florida, and South Pacific areas. These now mined/quarried products, originally formed by precipitation/ancient coral reefs, are sold in large slabs to product companies that then break them into smaller, various sized pieces and sell them to hobbyists as 'Lace Rock.' Except for initially lacking live bacteria and their white color, they are a usable product. As a test in 2015 used this form of rock to begin a nano reef aquarium and must say coralline algae was quick to begin covering the rock, and within five to six months the rock looked quite nice.

I've also seen beautiful fish-only systems using complete artificial reef structures containing various corals, while others were using manmade individual coral specimens that decorated very basic rockwork structures. Depending upon your goals, there are certainly a lot of possibilities as to what the rockwork in a finished aquarium environment can look like!

Polyurethane Foams

Every time I visited a public aquarium and saw their beautiful artificial decorations my brain would wander and would begin to think about how to create something similar in my aquaria, but at far less cost. In fact, when I visited Living Color in Ft. Lauderdale in the past and saw their beautiful artificial coral inserts I came away more determined to find a way to create more natural looking aquarium enclosures, and do so with less use of live rock. As time passed began to hear about the use of spray can polyurethane insulation foams, which are used to fill small spaces in construction projects, e.g., those between windows/doors and walls being used to cover inside aquarium side panels. It sounded interesting, but wondered about the toxicity of these products so visited some local home improvement stores and lumberyards to checkout the labels on some of these products. Even though there were many choices, with some having greater expansion rates than others, I was still not overly impressed with the words 'non-toxic' written into their fine print. Nor was I willing to search out their individual chemical safety records (MSDS – Material Safety Data Sheets). And besides, their color, mostly tan, brown, or white were 'very' unappealing!

During that timeframe while searching the Web became aware of two products, Great Stuff by DOW and a product called Spraydekor already being used by some aquarists, but was unable to find any clear-cut results or long-term use comments about them anywhere on the web! That alone made me feel somewhat uncomfortable about the use of these products as the web is usually filled with comments one way or the other. Yet, from what I could gather these products were simply spayed on flat laying side panels one at a time where the product would expand, and depending upon just how much was applied in places a lumpy-looking covering of foam resulted. Then pieces of dry rock, crushed coral, broken pieces of dried coral branches, and even some sand grains of different sizes could be pushed into this sticky, quick drying foam to produce a more natural looking background. In fact, it was said the material could be used to form caves and archways outside the aquarium, then moved into the aquarium and cemented in place.

While considering testing one of these polyurethane insulation foams for use on a small nano tank, I walked into a local aquarium shop and 'presto' there was a new 240-gallon reef aquarium in the rear of the shop sporting a 'foamed' rear wall! Wow, it really looked great as it was covered in a 'black' lumpy-looking mass of foam with coral frags inserted in various areas. The color was perfect, as it did not distract from other interior aspects and simply blended with the overall environment. The product used was called 'Handi Foam,' which is an expanding polyurethane pond product used to build waterfalls in Koi ponds or seal gaps or spaces between their rocks. It adheres to all surfaces except Teflon, silicone and polyethylene and expands about two to three times the extruded bead size, making it simple to finish with a lumpy looking, almost natural black lava-like appearance by controlling the amount applied in various areas. And best of all, its 'really' non-toxic as the animals in his system seen in the attached photo, were thriving.

And if not satisfied with the look of the finished product, it could simply be pealed off with no damage to the underlying surface, whether that's glass or acrylic. And if one did not want the product applied directly to the interior of his or her aquarium panels, it could be applied to a sheet of plastic/acrylic and it inserted, possibly to an already existing decorated aquarium if space allows! Yet, there was one situation with its application that needs some forethought, and that is its resulting foam covering is very 'buoyant!' This means that if you didn't want it to peal off on its own and float in your aquarium, it needs to be applied to a surface where some form of small structures/anchors, such as shallow strips of eggcrate have been cemented with silicone adhesive. If short lengths of one-square high eggcrate or similar fastening structures are not cemented to the panel, then rock will have to be leaned up against the coated panels to keep it from separating.

Furthermore, caves, arches, walls, overhangs, ledges and odd-shaped structures can be made outside the aquarium, which need to contain weights such as pieces of rock embedded in the foam to keep them from floating! Then these preformed items can be placed in the aquarium as desired. This lends many possibilities to what can be formed outside the aquarium, and how one's aquarium environment can be 'molded' to fit certain animal species!

In closing, home improvement construction type insulation polyurethane foam products are even far less expensive, but don't have a tract record as to their use in aquaria, whereas the pond products do. So I'm more inclined to go with their use. And as one can see from the photos, the final look of the aquarium interior is far improved, at least in my opinion.

Coral Trees

While reestablishing his 1200-gallon aquarium, aquarist Larry Read constructed what he called 'Coral Trees.' These were nothing more than sections of thoroughly cleaned branching coral sections that were cemented together to form a tree-like structure of varying height. They were then placed in the aquarium where small live corals were securely placed between the structures protruding branches. Since these 'trees' were free standing, i.e., its broad base sat on the aquarium bottom like a camera tripod, they could easily be raised for service or moved if need be. These trees basically allowed for better water movement in the aquarium since there was no usage of live rock, more openness and swimming space for the animals, and also far easier access to all bottom areas to help keep the system clean.


Eggcrate is the common name for the diffuser material utilized in overhead fluorescent lights. It's a plastic grid-like material usually containing square 0.5 inch wide openings. It is generally white, but can be found in black or chrome-like finish. Its very easy to cut with a hacksaw blade and can be cemented together with PVC cement or sections joined with plastic cable ties.

This material is ideal for making filter grids for overflow areas; chambers for chemical media; platforms for coral or rock; plenum grids for the Jaubert/NNR systems; strainer or drip plates for homemade trickle filters, overflow grids to prevent fish from ending up in the sump; or a flow-through walls to separate quarreling fish. Unfortunately, when seen inside the aquarium it detracts from the natural appearance of an aquarium environment. The white or black varieties are safe in aquariums, but the chrome colored variety is yet to be proven safe.

Maintenance Products

There's a wide variety of 'products' that help maintain the health of the system once up and running. In fact, there are so many that a separate book could be written on them alone. But lets look at some of the more important and/or well-known products along with their purpose and some usage hints. Probably the most widely used is that of activated carbon, so lets begin with it.

Activated Carbon

This chemical filtration substance is one of the more widely used materials when it comes to maintaining water quality. It fact, it should be considered a tool in our arsenal for helping maintain water quality. Not only is activated carbon readily available, it has been on the market for decades. It remains the choice of most freshwater and marine aquarists over other forms of chemical filtration media. It is frequently used in municipal water treatment facilities, home tap water filters, and air purification equipment. It has probably been utilized longer than any known filtration substance. Well, maybe resins have been used the longest as resin/ion exchange is discussed in the Bible, the Book of Exodus 15:22-25, and the Book of Numbers 19:5-17, where bitter water was made sweet by casting a tree into the water. The wood probably removed certain ions from the water and purified it to a certain degree.

Activated carbon remains a media of choice because it's efficient and cost effective. It also remains to this very day somewhat misunderstood and improperly utilized by some aquarists. To overcome this misunderstanding it's necessary to look more closely at carbon and what "activated" means and how to use and properly maintain it.

Activating Process

To begin, there are quite a few materials that can be used to make activated carbon. They include bituminous coal, lignite, peat, bone, nutshells, and wood. The best carbon for use in the aquarium is thought to be bituminous coal and second best may be lignite. The least effective, for aquarium purposes, is coconut nutshells and bamboo.

To make any of these materials useful, especially for aquariums, it must first be 'activated' and is heated to very high temperatures in the absence of air so as to drive off hydrogen and oxygen. The remaining char or 'charcoal' is again heated, sometimes to far greater temperatures in the presence of steam, air, or carbon dioxide to remove the remaining hydrocarbons and 'activate' the product by creating many tiny holes, passageways and crevices both inside and on the surface of the carbon particle. During this process, it can be given different adsorption characteristics by treating it with inorganic salts such as copper, zinc, phosphate, sulfate, or silicate. After the activation process completes, an acid or alkaline wash or rinse in some cases, will further change the carbon's adsorption characteristics and reduce these soluble contaminants that could leach into the solution its finally being used in.

Next, let's look at how carbon works and what it removes from solution.


The carbon particle can be thought of as a sponge, as it has large outside holes and crevices leading inward to passageways with ever decreasing smaller and smaller channels. This makes the internal structure of the carbon granule much more important than its outside surface area. In fact, when activated carbon 'surface area' is mentioned, it is really referring to its 'internal surfaces,' not its outer surface. The more internal channels there are, the more 'surface area' and the more places for molecules and matter (adsorbates) to flow into.

When this happens they become lodged and attached by both a weak physical force and what is termed molecule sieving. Adsorbates are then retained for removal from solution when the carbon is eventually discarded. This process is called 'adsorption,' and should not be confused with 'absorption,' which means to be simply taken into the media. It should also be noted that besides adsorption, other dissolved compounds can combine chemically with the previously adsorbed molecules and also be removed from solution.

Even though surface area (again, internal area) is extremely important, pore size and pore volumes are also important considerations. Pore size relates to the size of the opening leading into the carbon particle. Very small openings allow only small molecules to enter. Medium size pores allow more complex molecules to enter. Large pores not only allow various size or complex molecules to enter, but also suspended solid material. Small pore size is not efficient for aquarium use since the openings easily plug, thereby causing the internal areas to never fully become utilized. Pore volume pertains to the amount of open space inside the carbon particle. Within limits this simply means the more emptiness there is inside each particle the more space there is to pack in those molecules. The limiting factor here is the fragility of the carbon walls. Basically it can be thought of as the more internal surface area the greater its capacity and the larger its pore volume the better its efficiency.

Activated carbon in the aquarium removes dissolved organic molecules including non-polar proteins such as the phenols that yellow the water. Also removed are amino acids, iodine, carbohydrates, pheromones and peptides along with various heavy metals such as copper, chromium, cobalt, zinc, vanadium, iron, molybdenum, and mercury. Some dissolved gasses can also be removed. Some examples are hydrogen sulfide, methane, and ozone along with airborne fumes from paint, pesticides and cigarette fumes. Organic dyes like methylene blue and malachite green along with chlorine and chloramine are also removed. Activated carbon is very effective at removing substances used for treating aquariums for disease, e.g., copper, sulfa drugs, and antibiotics. Of course, it should not be utilized until the treatment cycle is completed.

Unfortunately it also removes some beneficial trace elements as noted above, yet this should not stop aquarists from using this efficient and economical chemical filtration media in a well-managed system. It should also be noted that initially activated carbon does not remove ammonia, nitrite or nitrate. The nitrogen filtering capacity will occur with aged carbon after nitrifying bacteria and possibly some denitrifying bacteria colonize the media. It will then provide some additional biological filtration. However the system should not depend upon this additional biological filtration, as it will be lost each time the media is replaced.


There are many choices when it comes to selecting which carbon to use. Sometimes aquarists are faced with products that look like carbon, are carbon, but have never been activated. Products like anthracite coal are sometimes sold as carbon (which they are). They are many times located on a store shelf next to activated carbon products. Their lower price may be attractive, yet because they have not been activated they are unsuitable for use in the aquarium. Always be sure the product label says the carbon has been "activated."

For activated carbon to be useful in aquaria, its pore size must be large, (macrospores), i.e., 40 - 5000 angstroms, such as produced in coal type carbons (bituminous coal). Many years ago, coconut shells were used to make 'activated' carbon, but after much hype they disappeared from the market because their pores were actually micropores (under 40 angstroms), where it was only good for gases/air filtration, not the larger varying size compounds that need to be removed in aquaria. It's my understanding bamboo produces even smaller pores than did coconut shells! In some cases it may be sold as burnt bamboo, a non-activated power-like substance. However, in my opinion, it's not an acceptable substitute for an activated quality carbon.

In fact, most aquarists and many distributors are of the opinion that bituminous coal is the better material for making activated carbon because it has proven to be good at removing 'gelbstoff.' Gelbstoff is a term used to describe large complex organic compounds responsible for yellowing water. However some lignite based carbons are demonstrating a very good ability to out-perform bituminous products. Nevertheless there is not yet enough firm data to prove this so bituminous coal remains my choice as to the best activated carbon material.

Most activated carbons are sold as Granular Activated Carbon (GAC). This generally refers to carbon in a granular form, which is a particle larger than 0.1 mm. How much larger depends upon what the distributor or reseller wants to market. Yet there are carbon-impregnated pads that tend to simplify its placement aspects in aquaria as it can be cut to fits various flow areas. As for the granular version, see General Attributes below for a recommendation as to ideal size.

When it comes to selecting an activated carbon it's something like buying a used car. Unless you're an ace car mechanic, you really don't know what you're getting. In fact, if I have any complaints with purchasing activated carbon it's that most companies fail to define the products technical attributes on its label. When this occurs the aquarist is left with only its general or visible attributes to make a judgment. What are the technical and general attributes of a good activated carbon product? Good questions!

Technical Attributes

When it comes to technical data the total surface area (TSA), pore volume (PV), and ratio of TSA to PV are the most meaningful. TSA is expressed in square meters per cubic centimeters (m2/cc), and PV in milliliters per cubic centimeters (ml/cc). A study by the president of a large aquarium product company indicates that the better carbons have a TSA of 450 to 550 m2/cc and a PV of 0.45 to 0.60 ml/cc with a TSA/PV ratio of 700 to 1000. When it comes to TSA, one tablespoon of activated carbon may have enough surface area to equal that of a basketball court! If the TSA is given on the basis of weight, a quality carbon should have a TSA of at least 1000 m2/grams. As to individual pore size (the size of the opening) it's discussed above.

General Attributes

Non-technical attributes are easier for most aquarists to use. These would be aspects like appearance, size, shape, does it float and make a hissing sound while becoming wet, and is the package labeled phosphate free. As for appearance, a dull black indicates a fairly porous particle and should be preferred over a shiny black particle, which may be less porous. The particle's surface should be slightly irregular or rather rough. The particle itself should be more round than flat-sided because flat surfaces block water flow when next to each other and thereby reduce adsorption sites.

Size is very important with the most efficient size being the approximate size of a pinhead or slightly larger. Some may think powdered carbon would be better than granular carbon, yet this is not so. A smaller particle size only increases its "outside" surface area and actually impedes internal water flow. Much larger than optimum size produces non-uniform flow and retards thorough penetration. Another good point to remember when selecting an activated carbon is to purchase one that takes up the most volume for a given weight. Keep in mind that TSA and PV, not the weight, is what should be purchased.

A good carbon product should also be quite buoyant and emit a hissing sound as water tries to find its way inside each carbon particle and fill its passageways and caverns. Any carbon that quickly sinks or emits little or no hissing sound can be considered less than ideal.

Always look for a statement on the package label that states the carbon product is phosphate free or at a minimum that tests have shown it not to leach phosphate. See the next topic for further comments on this important aspect.

Some companies refer to their carbons with terms like laboratory grade, pharmaceutical grade, research grade, or premium grade. This terminology has no value as to the actual efficiency of the product. Some distributors invent these terms to suggest or imply quality. Be cautious. If so labeled it may be a signal the product could be less than desired for aquarium applications. On the other-hand, it may be the best that particular brand has to offer. Check it out!

Also, the package price of activated carbon does not relate to its effectiveness. Some less expensive brands have been found to out-perform more expensive brands. The selection process can be confusing. It comes down to staying with either well-known brand names or word of mouth recommendations from fellow aquarists. In general, it's a buyer beware situation or actually applying what was learned here.

I've used the shown brands and many others and have found them to be 'excellent!'

Actual Usage

Activated carbon is usually placed inside a mesh bag and should be placed in a convenient place in the system where water will slowly flow through it. Not over it or too quickly through it. Keep in mind high water flow shear forces may simply wash away contaminants before they can be adsorbed. Slower moving water therefore allows more time, similar to dwell time in protein skimming, for the adsorbates to be in contact with the adsorbent providing greater product efficiency.

Laying a sack of carbon somewhere in the aquarium system, sometimes referred as the passive flow technique, with water flowing past it is in my opinion the least efficient way to use the product, although, 'some' elements will physically be attracted to the carbon particles. Yet, thorough penetration of the carbon particle or the entire carbon bed may never happen because detritus could block the carbon beds outer surface areas or water flows in the interior of the bed are stagnated and therefore mechanical sieving is not achieved.

If the ideal place in the system would have water flow through the carbon bed too quickly, consider dividing the bed into smaller ones and placing them in different areas in the system where flow is slower. The second bed could adsorb what a single bed might miss. By having a couple of small carbon beds and changing them at different times, i.e., the first bed in thirty days, the second bed thirty days later and then back to the first bed in thirty days, it will result in less of an impact to the loss of bacteria that colonize them and less initial trace element loss in the system. There is also better water penetration in smaller beds, therefore better utilization of its carbon particles.

Keep in mind many carbons are coated with very fine pulverized carbon dust when first removed from their container; therefore they should be briefly rinsed under tap water. The length of this rinsing should be short so the carbon carrying capacity is not reduced by any possible impurities in the tap water. Or, if possible use RO water to accomplish the rinse.

There are only about a half dozen manufacturers of activated carbon in the U.S. that I know of and most distributors of their products simply repackage it and sell it under their own label. And if the aquarist is new to the hobby the safest thing to do is stay with a product from a reputable company, which are mostly labeled as aquarium grade granulated activated carbon.

Even if the general selection tips mentioned above have been followed, some carbons contain small amounts of phosphate. Most well known authors recommend keeping aquarium phosphate levels at <.02 ppm because higher levels can lead to unwanted algae problems. Therefore look for brands that are advertised as phosphate-free as it's a good first step for algal control. However don't know of a brand that guarantees its product to be 100% phosphate-free, yet some are very close to it with remaining amounts so low they present no problems.

To alleviate any possible phosphate problems with a selected brand, suggest a sample of the carbon first be soaked in purified water (RO, DI or distilled) for a few hours before testing its solution for phosphate. If there is none, that could be the brand to stay with. If the test solution does contain phosphate, and before there is any further use of that brand carbon, it should be soaked overnight in purified water. Even then still advise caution, as this additional soaking may not remove enough of its phosphate to make it usable in the aquarium. The pre-soaking of new carbon will also minimize any pH impact (rises in pH) it may cause if it were immediately placed in the aquarium. Yes, pH is affected somewhat by fresh carbon. To what extent depends upon the alkalinity of the system, although most systems have very little difficulty with it.

One of the most often asked questions is how much should be used. That's difficult to answer, as it depends upon many variables such as bio-load, whether there is a protein skimmer or ozone in use, type of system filtration (Berlin method, trickle filter, algal scrubber, undergravel filter, fluid bed), and what type of material was used to make the carbon. The list of variables could probably go on and on as almost everyone has a different idea as to what impacts its usage and there are many what I like to call 'fairly well educated guesses.'

As for some of those 'educated' guesses, I've seen recommendations from small amounts to those bordering on the ridiculous, and won't go into all the details of who and how much was recommended because there were many. But will say that one of the least amounts suggested was about 4 grams per gallon, and even considered that to be slightly more than needed. Since I'm not talking rocket science here, recommend one heaping tablespoon of activated carbon, which is about 8 grams, per 5 gallons for fish-only aquariums. For reef aquariums, recommend the same amount of carbon per 10 gallons. This is not based on any scientific tests that I have accomplished, but what has worked well for me during the past years I've kept both simple and complex systems in the freshwater and marine hobby. Nevertheless, excessive usage in systems containing stony corals has induced bleaching within a few hours of installing a new batch of activated carbon! As for its maintenance, see Chapter 13.

Molecular Absorption Filters

These are generally known as Poly-Filters (P.F.) and are available from Poly-Bio-Marine, Inc., and without a doubt, at least in my mind, one of the most preferred/used chemical filtration products on the market. In fact, I've successfully used them in my freshwater and marine aquariums for many years. P.F. is a polymer pad, which has a polar surface and strains out organic pollutants. It is a very effective copper remover, both ionic and chelated, in fact, it's even better than activated carbon! Because it's an organic pollutant filter and polar, similar to the protein skimmer, phenols, proteins, oils, and phosphates tend to polymerize inside/bond to each other, locking themselves into the fibrous pad. And there is no desorption, as there is with carbon! Nor is there any way to clean these bonded compounds from the pads and when they are discolored all the way through, its time to replace them. They do clog easily however; therefore its recommended only mechanically filtered water flows through them if at all possible.

As a way to increase their total surface area, cut the pad into ¼ inch pieces if feasible, as explained in the canister filter discussion in Chapter 4. This way, there is simply more surface area to each pad used, providing a more cost-effective result.

Phosphate Adsorption Media

One of the many newer types of products seeing growing use is that of a media that will remove inorganic phosphate (orthophosphate) from seawater, therefore, help prevent the growth of unwanted algae. There are basically two forms, aluminum oxide, and ferric/iron hydroxide.

The aluminum oxide product is usually bead shape and used in similar ways as activated carbon and it's said it's capable of lowering phosphate to .02 ppm levels where it becomes irreversibly bound to the medium and will not be released back into the water. Aluminum oxide may also weakly attract carbonate, initially somewhat reducing alkalinity. Yet, since phosphate is said to replace the carbonate on the aluminum oxide particle, the carbonate should return to solution. It will also remove silicate, which is a diatom alga nutrient. Organic acids are also removed and in highly polluted aquariums this media should be replaced almost weekly. In well-managed aquariums, media replacement need only occur every 6 - 8 weeks. One further note, some aquarists report this type media can cause some leather corals (Sarcophyton spp.) to close up and remain closed for long periods. In some cases they may never come out of this closed state and slowly waste away. The cause is thought to be dissolved aluminum (Holmes-Farley, 2003), yet in my opinion, may be caused by over usage/more than what the manufacturer recommends, as I've used the product without harm to my leather corals.

More recently, products containing ferric hydroxide have seen a growing popularity amongst hobbyists as its said they are extremely effective and that even with overuse, it does not seem to directly affect the health of any animals in the aquarium. There are numerous brands, some taking a fine powder-like form, others tiny granules or that of impregnated pads. Those containing fine media are better used in a canister filter or a reactor designed for their use, e.g., Phosphate Reactor. If used in a sack, its mesh would have to be extremely tiny to prevent the media from escaping, and would quickly clog with detritus/bacteria with the majority of water flowing around the sack rendering it useless. There are reports this type product may cause a slight drop in alkalinity and pH, therefore those two parameters should be monitored somewhat more closely.

Phosphate adsorption medias are also found in 'sponge pad' form and can be placed in sumps or other areas where system water can flow through them. However, even though effective, they tend to act like any other media where water flows through them and soon act like a mechanical filter, needing frequent servicing. Yet for small aquaria, such as nano aquariums, they are quite useful and cost effective. Keep in mind, phosphate levels should be controlled at or below 0.02 ppm to discourage the growths of unwanted algae (its probably the most effective way to control algae excesses), and also from negatively affecting stony coral growth.

Nitrate and Phosphate Reducing Products

As mentioned in Chapter 4, there are also 'products' available to reverse the nitrification cycle (reduce nitrate levels) and also reduce phosphate accumulation in aquariums. Probably one of the first in the field of nitrate reduction for aquarium maintenance was that of 'Nitrex,' a carbon-impregnated material. Others then followed, with currently a wide array of products appearing on the market, with some explained in the following text.

And ever since that first product described below has appeared (Nitrex), I have personally experimented with brown sugar, vinegar, and vodka to encourage/boost bacteria activity to quickly utilize excess nutrients in the bulk water of some of my past reef systems. Those years of experimenting have, at times, led to bacteria blooms/cloudy water conditions, yet excellent protein skimming and/or additional aeration always helped to quickly resolve these conditions.

Nevertheless, the hours spent experimenting with these different products at different quantities and in different aquarium environments still left me somewhat unsure as to 'recommending' exact dosages for any them, except to say they merited 'experimenting' with. Now, with technology moving far forward into this area of products, the marketplace is seeing many new commercial products carefully designed for these purposes.

Nitrex Box

Somewhere in the late eighties, I used a product called the 'Nitrex Box' from Aquarium Products to reduce nitrates in my fish-only 75-gallon heavily fed aquarium containing a moray eel, triggerfish and lionfish. This small black box (about 8" x 5" x 1") was filled with a plastic chip-like material aptly named Nitrex, in which an organic/carbon-based food source was incorporated. Inside this special box, which was placed in a low flow area in the aquarium, denitrifying bacteria colonized the media and reduced nitrate into gaseous nitrogen by consuming the oxygen tied to the nitrate molecule. After a few days, bubbles of nitrogen gas could be seen leaving the Nitrex Box vent. As the nitrate in the box was broken down, a further quantity of aquarium water containing nitrate entered the box by diffusion. Therefore the box required no further care after being placed in the aquarium, except for replacing the media as needed.

I used three Nitrex Boxes to reduce nitrate levels that had climbed to over 100 ppm in this aquarium by placing one loaded box in the aquarium every thirty days, for three months. After ninety days, the first box was emptied and refilled with fresh Nitrex media. Thirty days later the following box was refilled, etc. Nitrate levels in this aquarium dropped to 40 ppm in two months. This product, which can still be found on the market, can also simply be placed in a mesh sack and placed in a low flow area in the aquarium.

Custom-made Unit

After the success with the Nitrex Box, I decided to build my own denitrification filter. Not because I didn't like the product, but because I wanted to test the operating parameters of a homemade flow-through denitrifying filter to see how well it would operate. I chose to use 'Nitrex' media as the food source for the bacteria.

I constructed a four chamber acrylic unit, the physical size as noted in Sketch "A" (Photo Credit: Marine Habitat Magazine) to use on my 125-gallon reef aquarium. The water from the aquarium would drip into chamber one at the rate of 100 drops per minute and be filtered by a small pad resting on an eggcrate support. The water flowed down through chamber one and then up through area C-1, in which a small, nylon mesh bag was placed containing a half package of Nitrex. The filter bag was placed so all water flowing through C-1 had to flow through the bag of Nitrex. This was also true in area C-2 and C-3. Then every thirty days the bag of Nitrex in C-1 would be moved to C-2. The bag that was in C-2 would be moved to C-3 and the bag that was in C-3, was discarded. A fresh bag of Nitrex would then be placed in C-1. The information below is a record of the results. The effluent from the denitrifying filter flowed into the trickle section of my system.

Sketch "A"

Nitrate in Aquarium
Nitrite in Aquarium
Nitrate in Filter
Nitrite in Filter
Week 1 20 0 20 0
Week 2 19 0 16 1
Week 3 17 0 10 0.8
Week 4 10 0 8 0.6
Week 5 10 0 5 0.2
Week 6 8 0 3 0.1
Week 7 5 0 2 0.1
Week 8 4 0 2 0
Week 9 3 0 1 0
Week 10 2 0 0 0
Week 11 2 0 0 0
Week 12 0 0 0 0

I should also note that in my reef aquarium there was a noticeable change in the size and appearance of macroalgae at 0.0 ppm of nitrate and not for the better. The macroalgae, Caulerpa prolifera, changed from a long and wide dark green leaf to a lighter green and smaller, more curly leaf. I shut down the denitrification filter and when the nitrate rose to 5.0 ppm three months later, the macroalgae returned to its pre-experiment growth level. If there was anything to be gained from this experiment it was that it is fairly easy to construct your own denitrifying filter. And, that Nitrex, which is still available on the current market, was an easily controlled food source for the bacteria. But if you like macroalgae in your aquarium, it may not fare well at very low nitrate levels.

While that experiment was running, I discussed the Nitrex product with Dr. Craig Jones, one of the world's best scientists in my opinion when it comes to microbial processes and the very interesting subject of just how complicated 'water' really is! While discussing the Krebs cycle, mention was made of using vodka, a very good grade, i.e., 90 proof or higher, as the carbon source. Also mentioned was the use of 'brown sugar' as a carbon source to resolve bacteria films (now called cyanobacteria). I thought the vodka approach interesting, and after cleaning out the test system, restarted it without Nitrex and simply dripped vodka into the first chamber. I used a simple apparatus to drip the vodka into the sump test unit. - Nothing more than an inverted plastic soda bottle with a small inline control to adjust the drip rate.

The results varied greatly, as did the drip rate, but after several months of trying different drip rates I came to the conclusion that vodka did work quite nicely. And I noticed my skimmer produced darker foam. Nevertheless, got away from using vodka since my fishes were members of AA, and decided it was probably better for me than them. Kidding aside, it did work very well and effectively minimized nitrates.

Those were the early days for carbon-based products for denitrifying purposes, and now technology has moved much further ahead, and numerous products are coming to the market for this purpose and that of reducing phosphate.


Another 'product' (Absolute Zero - Nitrates) that came about in the later 90's and still available today as its been highly improved. It contains the chemical compound Cozymase, which produces a bacteria bloom in the aquarium's bulk water that in turn consumes nitrate. This bacteria, or should I say the bloom is cleared/harvested by using a quality protein skimmer. Since bacteria blooms deplete oxygen content, I recommended additional aeration be employed if using this product. The manufacturer recommends continuing dosages at reduced levels until the aquarium's natural denitrification abilities can maintain low nitrate levels. Letters from users all recommended utilizing a high quality protein skimmer and/or increasing dissolved oxygen content when using the product.


This liquid product from CaribSea, when dripped into aquarium water, precipitates dissolved phosphate, removing it from solution. I've used the product and found it a quick and simple way to maintain low phosphate levels in small/nano aquariums, although it did somewhat deplete alkalinity. Therefore, when this product was occasionally used as needed, alkalinity was increased slightly prior to its use.

NO3 - PO4 X

This Red Sea methanol-based product has also been experimented with in a nano aquarium. It quickly reduced my nano system's NO3-N level with very minor doses of the product from 5 ppm to near zero in about ten days and phosphate, which was already quite low, to less than 0.02 ppm! In fact, the attached photo shows nitrogen degassing in the aquarium's sandbed about two weeks after applying this product. Quite amazing! Yet have experienced some substrate binding, no doubt from fast forming bacteria colonies, which is expected when using these type products. They were simply and easily broken up, but do recommend monthly surveying the sandbed when using any of these type products. Nevertheless, as of this writing, can say I've had good success with this product, and you might want to try it in your system if needed and let me know its results.

There's no doubt I could go on and on about these products, nevertheless pick a product, try it as recommended and if possible let me know your thoughts and if feasible, might place its results with due credit in this section of this vast book for others to view.


Whether it's fish-only or reef aquariums, various elements and minerals are being consumed/utilized by its animals and algae, and water changes with excellent brand sea salts will not fully replenish all of those used. Therefore, to maintain near natural quality seawater in the aquarium various additives/supplements will be needed and many aquarium companies excel at supplying a variety of products, both in liquid and powder/granular form to enhance/maintain seawater at near natural chemical parameters.

Available products and their purposes are many, in fact, too many to list here. Nevertheless, it should suffice to say they could loosely be 'grouped' into categories with 'some' examples you may find helpful in deciphering the multitude of these type products on today's marketplace.

'Major and Minor Elements' such as calcium, magnesium, and strontium.

'Buffers,' such as that for controlling/raising pH and/or alkalinity

'Enhancing and optimizing coral growth and colors,' which may be individual elements such as Iodine or others, or combination products covering a broad spectrum of various other important elements/trace elements.

I leave you with the following advice; there are many easy to use additives and highly recommend being absolutely sure they are needed prior to their use, and if needed, follow its dosing instructions. Keep in mind overdosing some of these products can cause problems!

Furthermore, any additive/supplement from a quality manufacture should have its ingredients listed on its label. If not, recommend not using it!

Again, if unclear as to its purpose or not sure about its need in your aquarium, contact other hobbyists, maybe someone in a local aquarium society, or me through this website with your concerns/questions.


Let's now move to Section Two, Chapter 7 - Filtration Processes, and discuss the mechanical, chemical, and biological aspects of this 'most' important component of marine aquarium husbandry!