By Bob Goemans
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Bob Goemans corresponds with Jim Reid (Melbourne Beach, Florida)

Jim Reid (Melbourne Beach, Florida) writes...

Hi Bob,

Bruce at ROWAphos told me to email you regarding my DSB. I'm having some serious problems with phosphate and hole in the head. My aquarium is 380 gallons along with 200 gallons in the sump. The tank is made of acrylic in a normal rectangle shape. It has a DSB that is on average 6" deep. It's a SeaFloor special grade sand by CaribSea. It has been set up for 4 years. It's a fish only live rock system. The fish population consists of:

* 1 Majestic Angel 6"

* 1 Regal Tang 7"

* 3 Purple Tangs 3-4"

* 1 Clown Trigger 7"

* 1 Psedochromis 4"

* 12 Chromis various species around 1.5"

* Many small orange worms living in the sand bed

* Fiji Live rock around 300lbs

The tank is fed by a Eheim Feeder using New Life Spectrum pellet food supplemented by various dried algae and frozen cube foods. This population has been maintained steady for the four years. The fish have grown very well, but over this past year the tangs have all developed hole in the head disease. Due to this happening I've implemented:

* More vegetable matter in their diets

* Increased water changes to biweekly

* Added a grounding probe

* Changed all the lights

* Added small weekly trace elements from Kent Marine

* Soak food in Selcon and Kent Zoe vitamins

* All make up water is filter by a SpectraPure RO/4 position DI filter

This problem, even with the above changes, has continued on and become even worse.

Current tests indicate the water quality as follows:

* Ammonia 0

* Nitrite 0

* Nitrate 20 ppm (I've always felt this low because of the DSB)

* pH 8.3 daytime in the middle of the lighting period

* pH 7.6 - 7.8 in the middle of the night

* Alkalinity 3.0 slipping to 2.5

* Phosphates range from .25 up to 1ppm (I can get it down to .25 by using various PO4 removers.) Calcium 340

The filtering is done by the live rock and the sand bed along with an AquaMedic 5000 7' double needlewheel skimmer, and a UV sterilizer. The flow thru the system is done by a 1/3HP Dolphin pump flowing directly back to the aquarium at ground level. The tank has 6 overhead water pumps each pumping 750GPH aimed down towards the sand bed.

My problem is that for the first 3 years I never had an algae problem and my tangs appeared very healthy. During the past year the tangs rapidly developed the hole in the head problem but continue to grow but the algae fight is horrible. I can clean the tanks glass on Monday and by Wednesday all over is caked up green/brown algae. I can see the algae build up over night but within two or three days it's horrible. I've consulted with several people who feel that my sand bed is the source of my problem and that I should completely eliminate it. I was told to perform a test with a gravel washer. I sucked the sand up in one corner only to find very terrible nasty dark dirty water. I know as a diver that when I stir the sand bed up it is also dirty so I figure this must be somewhat normal. Some individuals have told me I should have more sand stirrers however they always get eaten. I've been considering purchasing some type of fluidized filter to run a large volume of ROWAphos hoping to rid the system of the PO4. During different discussions about using the ROWAphos I've been advised to eliminate the sand bed by several different people. My problem is that this is a very large job with about 500lbs of sand that I purchased because of its good filtering ability. Please provide me with your thoughts on how to remedy my problems. This is very frustrating. Also, what methods are available for using the ROWAphos in large quantities?

Thank you,

Jim Reid

Melbourne Beach, Florida

Bob replies...

Hi Jim,

Thanks for an excellent email, and I see several areas where improvements could be made in your system. And I should note, that after 60 years in the hobby, I've seen much of what you describe numerous times. But unfortunately, I don't have any 'magic' cures that will do it overnight, as my recommendations will take much effort on your part. But if the system is worth saving/improving, then these suggestions/comments will provide a path that will lead in that direction. And since I've never been an aquarium product company employee, or have been paid by any of these companies to use my name or say nice things about them, you and everybody else can count on the sincerity of my answers.

Before I begin my recommendations, your bioload, fish wise, is quite reasonable for your size aquarium. In fact, it's probably the reason why your system has been so successful for a long period of time. But a combination of things is now catching up with you!

As for these recommendations, I first need to describe why a very DSB, such as yours, is largely a mistake when compared to a shallow bed of about two inches. - Those that create deep sandbeds are of the opinion they can keep the nitrate level in the bulk water low and that different microcrustaceans and worms will also help keep the bed healthy. That's mostly a misconception and in my well-experienced past, and after spending 12 years researching sandbeds in the wild and in closed systems (AKA aquariums), have found them to many times turn into what could be called a septic tank, where nutrients check in, and either don't ever check out or become something worse. That's because those who establish such deep beds do not understand the microbial processes occurring in that bed, and/or do not perform adequate bed maintenance. They are of the opinion that the nitrate formed in the upper portion of the bed will be reduced/oxidized to nitrogen gas in the lower bed, therefore ridding the system of that alga nutrient. And the deeper the bed, the more nitrate will be eliminated. That's only 'half' the story! What really happens, is that nitrate is formed in approximately the upper half inch of the bed (that is if the sand grain size is about 2 - 5 mm; if smaller, far less depth area, with mud like particles probably having a depth of a millimeter where ammonia is changed to nitrate), and is attracted deeper where it comes across 'two' different 'classes' of bacterium, not one that lives solely in the so-called anaerobic area. What really happens, is that in the upper portion of this 'so-called anaerobic area,' where there still remains some oxygen, (past tests indicate this to be .5 to 2.0 ppm (B. Goemans & S. Gamble, 2001), an area that should properly be called the 'anoxic' area/zone, a form of denitrification called "Dissimilatory Denitrification" occurs. And the class of bacteria performing this process is facultative anaerobic heterotrophs, with the result being that the nitrate is reduced to nitrogen gas. But these bacteria only exist in this zone where this level of oxygen exists! Below this zone, and no doubt the greater percentage of bed depth, a zone exists where there is less oxygen or none at all, and this zone/area is the true anaerobic area. And in this area, only obligate anaerobic heterotrophs performing the "Assimilatory Denitrification" process is where nitrate is only reduced to that of ammonium, and no further! And of course, ammonium is the primary alga nutrient. Now this is not to say all this ammonium leaches up through the sandbed and into the bulk water, however, in this type deep bed, that ammonium is in a state of constant flux where some of it changes back to nitrate, and or in some instances, some does leach upward through the bed, with some of it entering the bulk water (both nitrate and ammonium). Unfortunately, where ammonium is concerned, we can't test for it. Therefore, this very real possibility should be considered when there are increased unwanted algae growths in the aquarium that contains a DSB. There's also another situation with DSB directly on the aquarium bottom, as nutrients are positive charged (That's why protein skimmers work, as the positive charged nutrients are attracted the negative charged air bubbles!). And the deeper you go in the bed, the more negative its sandbed charge becomes! The more depth in closed system beds, the more opportunities for system balance to become affected.

And furthermore, when the sandbed surface is covered by an overabundance of rock, two more poor situations arise. The first is that under the rock directly in contact with the sand, there are no aerobic autotrophs living in the upper sand breaking down the inorganic ammonia since there is no oxygen present in that level of sand. Therefore, the only bacteria present in the sand below the rock are the obligate anaerobic heterotrophs producing ammonium! And I could also go into the sulfur cycle, where dangerous hydrogen sulfide is produced in areas such as this, but if not disturbed, should pose no immediate problems. Yet, the possibility for this compound existing is enhanced in these areas and should be at least thought of when attempting to vacuum the sandbed.

And that brings me to the second drawback with too much rock, and that is it becomes impossible to vacuum the bed in those areas, which just adds to the accumulating detritus. (Vacuuming should be done monthly in my opinion.) And that takes me to your statement of how dirty the sand was when you attempted to vacuum it, and that it compared to the sand found in the wild. Keep in mind there's a major difference between closed systems and the wild when it comes to the exchange of recycled/quality water crossing a section of sand in the wild, and that in your aquarium. Closed systems are just that; a very confined space depending upon a microbial balanced environment and that of a bioload that won't exceed it. And that does not often happen in aquaria! In the wild, billons of gallons flow over that dirty sand section, carrying 'away' any pollutants coming from it.

That's why so many other types of equipment and additives are required in closed systems, and why the 'one more pretty fish' routine gets so many hobbyists in trouble! There's just so much water in the closed system, and one needs to recognize that its important to stay within what should be well-established and commonsense goals. And before I leave this 'too much' live rock discussion, consider the rock no different than a very deep sandbed, as the majority of its microbial processes don't differ! (Ever wonder why algae, micro or macro seem to grow so well on the surface of the rock? - Gee, could it be a source of some ammonium from its 'truly anaerobic process within!)

And the gap between nighttime pH and mid lighting timeframe is an indicator that system alkalinity/magnesium level is probably out of balance. Without sufficient buffers in the system to dampen the swing caused by increases (dirty sandbed!) or decreases to carbon dioxide levels between day and night, pH can experience a wide daily range. First check your magnesium level (I use the Salifert test kit for this parameter) and then relate that to your Specific Gravity (SG). If your SG is 1.022, your magnesium level should be approximately 1100 ppm. If your SG is 1.026, your magnesium should be about 1280 ppm. You can go on-line for charts that note the correct levels as they relate to each other. You might even want to consider a quality calcium reactor (would help correct the dropping calcium and general alkalinity situation, and augment the magnesium situation, yet would still need to be monitored and corrected from time to time), or using one of the better two-part liquid calcium/buffers to better control this disparity, however first bring it under control (I use either ESV or Warner Marine magnesium additives to keep my systems in balance). Then there are major water changes that would also help bring the balance of elements and compounds in the bulk water more into balance.

And before I make a recommendation on your bed, let me address the thoughts on infauna maintaining the bed. I've always been fascinated with this subject, as I kept seeing comments that these little creatures will maintain the sand in a healthy condition. However, I've never seen just how many of what type creatures would do that! In all fairness, the right combination of microbial and infauna processes in a closed system where its bioload would not overwhelm said processes, would work splendidly. But in 'aquarium land' I wouldn't expect that to happen too often! Therefore, knowing that infauna need oxygen to live, they aren't going to inhabit true anaerobic areas, nor do I find it possible to direct each and every crustacean or worm to take certain paths so as to evenly ply the bed. Therefore, I need to look to things I can control, and infauna is not one of them. So in this aspect, let nature take its course, and if some infauna additions are possible, try them, but don't count on them to do wonders! And keep in mind that sand sifting sea stars are worthless in my opinion, as I've tried them and they simply consumed all my sandbed infauna that was of value!

Lets now address the phosphate level in your aquarium, which is far too high. And which gives the algae the 'energy' it needs to get/keep it growing (ammonium/nitrate provides its food source). Actually, most phosphate in our aquariums is due to the food fed and the quality of tap water used for evaporation makeup or water changes. And this is where we need to go, but want to mention the following, as it's been said anaerobic areas, where obligate anaerobic heterotrophs reside, accumulate phosphate. That sounds ominous, but the anaerobic area with its lower pH and redox is an efficient user of the oxygen electrons tied to the phosphorous element; therefore phosphate is quickly reduced to other phosphorus molecules and ions. That's a plus for the DSB as the majority of its substrate is usually in an anaerobic state.

It could then be said phosphate accumulates anywhere where it's not attacked for its oxygen suggesting that in more aerobic and anoxic bed areas there would be greater accumulation since oxygen is readily available. However, that's also not accurate! In those areas it's mostly bound to calcium and manganese where it's quite stable because it is very easy to maintain its 'charge' balance. Therefore phosphate is usually not available for uptake in substrates unless associated with reducing conditions.

On the other hand, where there is infauna (your orange worms are probably bristle worms - Eurythoe complanata, which if small, are not a threat), they depend on getting oxygen to live and have to link with the substrate surface, whereas microbes do not. The tunneling processes (irrigation) by infauna can bring phosphate to the bed surface. Yet, even though feasible it would depend upon the size and type of infauna, e.g., large worms. Nevertheless, when it does occur it's in the form of orthophosphate, something not registered on aquarium phosphate test kits and could help cause phytoplankton and algae blooms. Keep in mind infauna also ingest sources of phosphate and produce phosphate-laden wastes, however, they should be considered more movers of the compound than users.

So that brings me back to "most phosphate in our aquariums is due to the food fed and the quality of tap water used for evaporation makeup or water changes." Need I say more? Probably so, therefore lets begin with what you're feeding - and pellets of any kind would not be on my list, as they are too difficult to be sure they are 'all' consumed, and not finding their way to the sandbed surface and becoming a major source of nutrients in your bulk water. I look at pellets as an easy and fast way to feed certain animals, however, not always the best way to handle the situation. I prefer to feed often, and only small amounts that are eaten within a few minutes. But I'm retired, and can take the time to enjoy seeing my fish eagerly take the food numerous times a day. But for those not able to do that, there are various nori strips that can be used in so called lettuce clips that work quite good throughout the day. And there are many different frozen foods available that can be fed frequently during the evening hours when the aquarist arrives home from work. And as for frozen food cubes, they should first be removed from their little containers, then allowed to soften in the air, not in a dish of water, then be broken up and distributed through the aquariums water so the fish eat almost all of its contents. That way, its vitamins and minerals enter the fish, not the surrounding water. If you're placing the cubes in a dish of water to first soften them up, that's an incorrect way to handle them. You're then wasting a good portion of its vitamins and minerals in that water. And if dumping the entire contents of that dish in the aquarium, it only increases the nutrients in the bulk water. And do not use Iceberg Lettuce, as that has no redeeming qualities. Better control over the feeding processes will help reduce the phosphate level. And since you have begun using an excellent RO/DI to control any phosphate/nitrate in your tap water, we won't go there, as that's the right direction there.

Then, the next thing to discuss is the use of the ROWAphos product, or any of the new ferric hydroxide materials (iron-based products) designed for very efficient phosphate removal correctly. And one way to do that is in fluidized filters or similar devices. And since I've used this product I chose to use a Fluval canister filter, which has three internal baskets. I first filled the lower basket with activated carbon (I use either ESV or Boyd Chemi-Pure) in a sack of course, and I also cut up a Poly-Filter into small pieces (More areas of absorption that way). That fills the first basket. In the middle basket I place a layer of filter fluff and spread five tablespoons of ROWAphos over the filter fluff. Then cover the media with another shallow layer of filter fluff. I do the same in the top basket and change the media when there is the first sign of any phosphate reading on my test kit. Suggest you get the largest size Fluval, and use twice the amount of ROWAphos as mentioned. And either use the Salifert phosphate test kit, or try and get the Merck Phosphate test kit from those who sell the ROWAphos product, as it's 'extremely' accurate, but a little more pricy.

To sum up the water quality/phosphate/algae situations, I recommend 'carefully' reducing the level of sand in the aquarium to about two inches. If this means removing some of the rock, so be it. I realize it's easier said than done, but in the long run, it will be worth it. I would recommend doing one third of the aquarium one month, then the next third the following month, and a month later the remaining. And while doing each third, be on the lookout for dark areas in the sand, as they may contain hydrogen sulfide, and if found, be sure to siphon out the entire dark area and not allow any of its water to reenter the aquarium. Bring each third down to the sand level suggested, and reinstall some of the rock, first cleaned of an unwanted alga, so it allows for as much sandbed surface exposure as possible so you can perform useful monthly vacuums thereafter. And at the same time better control what is fed, and continue to monitor the phosphate level. Also consider getting ozone equipment, including a controller and shoot for about 350 - 400 ORP. Once the entire aquarium is cleaned, add 50 - 100 Astraea snails, as they are far better than the turbo species. Then stay after unwanted algae growths by siphoning out new growths. Over time, the system will greatly improve and you and you pets will again be happy campers!

Lets now address the Hole in the head situation. Head & Lateral Line Erosion (HLLE) often appears as a pitted area on the face and/or along the lateral line of the fish, the cause of which has generated much conjecture in the aquarium world. That of dietary or vitamin deficiencies, stray electrical current or free electromagnetic fields, exposure to heavy metals, protozoan organisms, poor water quality, stress, the use of activated carbon, certain medications, and even various viral and bacterial infections has been put forth as possible causes.

It would seem reasonable to assume that any of these conditions could (possibly in conjunction with others) provide the emphasis necessary to get this malady going. Until more evidence is presented, I'm of the mindset that a poor or inadequate diet combined with stress and poor water quality (in that order) remains as one of the leading causes. Furthermore, I'm of the opinion that HLLE could be considered comparable to rickets or beriberi in humans, and that poor water quality and stress no doubt irritates a vitamin/mineral deficiency and the deteriorated areas on the fish body then become a haven for bacteria and viral infections.

I base a portion of my position on an incident that occurred over twenty years ago when the president of a local aquarium society was given a Purple Tang that had come into a local aquarium shop riddled from head to tail, or what was left of the tail, with HLLE. The fish was placed in a 100-gallon aquarium that contained some lionfish and lots of good hiding places. The water quality was excellent and the tang was fed flake food soaked in an all-natural multi-vitamin solution and was also given the excess macroalgae from another aquarium. The flake was fed as often as possible in the beginning, sometimes as many as ten to fifteen times a day. Only a small pinch of treated flake was dropped in the aquarium, never any more than the fish would eat in a minute or two. Within a few months the fish was almost fully recovered and was beginning to look like it just came from the ocean! About a year later the above remedy was suggested to a fellow hobbyist in England, who was having a severe HLLE problem with one of his Angelfish. After trying the recommendation for a few months, he wrote back saying the fish was returning to normal.

Keep in mind that most often, Tangs and Angelfish are among the most affected, as most are herbivores where their diet consists mainly of algae. And, since micro and macroalgae contain a wide variety of trace elements and vitamins, the lack of a proper supply of these elements and vitamins may just be part of this problem. Therefore I'm of the opinion that diet may be among the leading causes. Also, keep in mind that broccoli, which contains Vitamin A, C, E, and some iodine, may be something to occasionally feed fresh or blanched to those fish requiring vegetable matter in their diet. Additionally, I should also include here that fish exposed to natural sunlight don't seem to be affected by this malady, possibly due to the fact that Vitamin D synthesis requires exposure to sunlight. It could be there's a connection there also, although this is only anecdotal at this time, based on personal observations. Ultimately, however, further research on this condition is required, as there are still many unanswered questions as to the true cause(s) of HLLE. Nevertheless, I believe you have instituted a series of corrections that should help, however, I also 'highly recommend' feeding fresh macroalgae, preferably either or both Caulerpa mexicana and C. prolifera, as these two macro's seem to be the most tasty! And I would try to keep a supply of these in the aquarium so your fish can graze upon them throughout the day. And this should remove the need for an autofeeder, which, will do away with uneaten food products that eventually can lead to diminished water quality.

Furthermore, if HLLE has got to the point where secondary infections may exist, there's a Chinese tea extract that is found in a product called MelaFix, which would be helpful. I've used it to heal secondary bacteria infections on some fish, even in reef aquariums.

I realize a lot has been said here, but have gone this road with many others in the hobby, and most have come back saying it was worth the effort, and they appreciated the time taken to take them through a situation that could have put an end to their hobby. So the road is clear, at least in my opinion. Truly hope this helps.


Jim Reid (Melbourne Beach, Florida) writes...

Dear Bob,

Thank you so much for your reply. I intend to put your concepts to work immediately. I'm going to be starting over in the next few days. My methods will be as follows:

1. Removing the sand bed as you described in 3 parts.

2. Adding ROWAphos to the system. Question: I've been told that my volume of water will require using 1.5 to 2.0 liters of ROWAphos. Will this kind of volume fit in the canister filter?

3. Checking the Magnesium levels and adjusting accordingly.

4. Adding ozone, I already have an ozone unit I just need to get a controller. Question: Which one is your choice?

5. Making water changes

6. Adding snails would help however my fish will be having dessert with these guys.

7. Continue to address the hole in the head with the tangs. I could increase the amount of feedings but then I would be adding more PO4 unless I use natural methods such as the Caulerpa. I will try to locate a source for this. I do have a source of Gracillara algae, which I've not tried.

I would like to take the time to thank you so much for taking your time to help me out with my problem. Not many people in this day and age do that.

Thank you so much,


Bob replies...

Hi Jim,

You're welcome, and as for you're questions, if the recommended quantity for ROWAphos is that great, then I would consider using one of their fluidized bed devices, as I'm not sure if the largest Fluval can handle that much media.

As for the ozone question, keep in mind it needs to be dispensed through a protein skimmer, (and its effluent needs to pass over a carbon bed before returning to the aquarium) and suggest not using your main skimmer to do this, as it will far reduce its foaming effectiveness. Simply purchase a cheap unit that will still move a lot of water through it, and apply ozone to it. That way, you won't be concerned about its lack of foaming ability once the ozone is applied to it! And if possible, place this second skimmer somewhere in the flow of things after the first skimmer. Simply more efficient that way. And as for a controller, I've in the past used the Red Sea ozonizer and controller and found it to work extremely good.

As for the snails, try some, and if they continue to be eaten, try a Lawnmower Benny.

And keep me posted, as your success is as important to me, as it is to you.


Jim Reid (Melbourne Beach, Florida) writes...

Hi Bob,

Again, thank you for your interest in my personal success. I find it hard to believe in this day and age that some people still try to help others. I actually started to remove a small portion of my sand bed but my hose continues to clog up. I'm going to the Depot later and I will purchase a 1" hose or possibly larger to suck the sand out.

Again, thank you for your help.


Jim Reid (Melbourne Beach, Florida) writes...

Hi Bob,

I wanted to let you know that I started on my journey today. I removed just over 1/3 of my sand bed today. I relocated the rocks in this area. This sand bed area was 'horribly dirty.' I tried to only suck the sand up but a lot of this dirt drifted into the water. It was very bad. My skimmer just immediately began pumping out horrible black guck. Seems the fish faired the storm so far. This evening it is still stirred up but they seem o.k.

Thank you,

Jim Reid

Bob replies...

Hi Jim,

Yes, this is a messy procedure, but in the long run, it's worth it. Hang in there, and siphon out any visible accumulations of detritus that become accessible in these early stages. Isn't it amazing how filthy deep beds can get!


Jim Reid (Melbourne Beach, Florida) writes...

Hi again,

I wanted to keep you up to date. I've done as you said so far as I've removed the other 2/3's of my un-needed 'plugged up' sand bed. (Had to do 2/3's as it was loaded with hydrogen sulfide in many areas) I've done about 5-55 gallon water changes in the process of removing this sand. I've implemented ROWAphos, which has been running for 2 full weeks. I'm using it in two of the Little Fishies reactors. I immediately stopped the pellet fish food and have been giving the tangs and Majestic Angel live Red Gracillara algae that I'm collecting. They seem to enjoy this alga.


Bob replies...


There were more letters, but to shorten a long story, I finally phoned Jim, as he gave me his phone number in an earlier email to get the latest results. He said that after cleaning the remaining sand and lowering it to 2 inches, the phosphate level dropped considerably as did algae growth. Further use of ROWAphos has brought phosphate and unwanted algae growth to nill!. His fish still have some HLLE, but it has also shown signs of improving. He again expressed his thanks for my help. (We aquarists are all brothers and sisters in my opinion!)


Phosphates; Head & Lateral Line Erosion (HLLE); Deep Sandbed Method

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