Product Review The Ultimate DI System

Very early last year I was in the Phoenix Arizona area visiting several aquarium product companies. I normally checkout the area on a monthly basis, only 160 kilometers north of where I live in Tucson, because their population and selection of shops is so much greater than our Tucson area. One of my stops was at the SpectraPure (1) facility to check on the availability of what was rumored to be a new type Deionization (DI) system. Unfortunately, the owner was away on a business trip, however, his wife thought I might be interested in seeing a "Star Trek" looking device hanging from the ceiling in their workshop. It was a 2 meter long tube, about 8 cm in diameter, extending out from a 25 cm oval-shaped housing.

I realized this was something that looked like the first generation sulfur lamp built by Fusion Lighting, called the Solar 1000 Lamp. This one was a little smaller and was informed it was a second-generation lamp. I momentarily forgot about the new DI system and asked if the lamp could be turned on. I had heard these lamps are so bright it is impossible to look directly at them.

I should note the sulfur lamp uses radio frequency waves to excite a golfball-size bulb filled with sulfur and argon gas, which rotates at 3000 rpm in its oval housing. The argon heats the sulfur into a gaseous form and the energy produced, a broad visible spectrum, is radiated out into the glass tube. The lamp itself remains cool, yet the housing contains a large muffin fan to cool the spinning ball.

While the lamp was spinning up, which took about a minute, it was explained the lamp uses a 1000 watts, produces over 130,000 lumens, and should last for twenty years without any loss of spectrum. It also does not generate any ultraviolet or infrared light. Within a minute it was impossible to look directly at the lamp! The noise generated by the unit was mostly that of its muffin fan, so noise would not be a major drawback. Cost of this model, which I understand was a prototype model and not being produced, was about three thousand dollars. The owner's wife asked if I wanted to take it home for a fair price since it was hardly ever used to light the workshop area just too bright was her comment. I could just imagine walking into our home with this monster! I would probably be sleeping with the dog that night. Anyway, I believe SpectraPure wants to sell it and if interested you may want to discuss it with them.

If you have the means and whereabouts for such a device your reef aquarium would love it. Your spouse might be another thing! I should mention, however, what was lit in the room appeared somewhat washed out and the lamp may need to be supplemented with some actinic lamps. Since the above information is from a verbal discussion and not from any specification sheets, I would suggest contacting Pure Food Hydroponics via the Internet for more details if such devices are of interest.

Anyway, this product review is really about a new DI system, but I thought the above might be interesting. About a week later the owner of SpectraPure, Charles Mitsis, called to discuss his new DI unit. It was ready for my testing and he mailed a unit to my home. After actually testing this new equipment I am very sure you and "every" other hobbyist and professional aquarist will want their water purification system to have the same result the "Ultimate DI System" can provide.

For those not familiar with the terms used in water processing equipment, e.g., Reverse Osmosis (RO) and Deionization, first some background.

Reverse Osmosis

Only freshwater is used in aquariums to replenish evaporated water and/or for water changes, whether that be in freshwater or marine aquariums. Unfortunately tap water sometimes contains pollutants that can be harmful to aquarium inhabitants, especially those in reef aquariums. Levels of nitrate, phosphate, and silicates in tap water may be high enough to cause unwanted algae growths. Small amounts of heavy metals such as copper can easily kill invertebrate. Many hobbyists find it necessary to first process tap water before using it in their aquariums.

The RO process was first discovered in nature when sea birds where noticed drinking seawater and appeared to be unaffected by its high salt content. Upon a closer look it was found the birds actually filtered the seawater through a membrane in their beak, resulting in only freshwater being taken into their systems. Further experimentation with the process led to the development of water purification equipment that is capable of removing unwanted dissolved salts and organic compounds.

For aquarium purposes there are basically two types of membranes used in RO equipment: cellulose triacetate (CTA) and thin film composite (TFC). The TFC membrane is far superior because its rejection rate of pollutants is much higher, about 90%, and does not readily breakdown from bacterial attack.

When water flows to the RO membrane only the very small almost pure water molecules can pass through its tiny holes. Larger contaminant molecules can not pass through and are rejected via a drain line. All RO membranes have difficulty rejecting nitrate and silica, which are two of the three main plant nutrients. Phosphate, the third plant nutrient is better rejected; however certain conditions can also make it difficult to remove.

Since the membrane is the heart of the RO system it must be protected from certain impurities and/or any disinfecting solutions in the in-coming water supply. Therefore a Sediment Prefilter should first receive the incoming water to protect the membrane from coarse solids that would quickly clog its very small holes. Its effluent should then flow to an in-line filter containing activated carbon or preferably a carbon block filter. Since TFC membranes are very sensitive to chlorine and water supply companies generally use it to disinfect water lines, a carbon prefilter is a must. Besides removing chlorine and pesticides some other volatiles and heavy metals will also be removed by the carbon.

Replaceable sediment and carbon prefilter cartridges along with a quality brand TFC membrane are the important components of any RO equipment. Most carbon filters should be replaced every six months and the sediment filter once a year. The RO membrane can last for many years.

When it comes to selecting RO equipment you'll find them "rated" in how many gallons of product (usable) water they will produce in a twenty-four hour period. Units that can supply 10 to 50 gallons per day will usually meet most hobbyist needs. Bear in mind water pressure is an important operating parameter for this type equipment. Municipal water companies supply that pressure in their delivery systems and 45 pounds should be considered minimum, 55 pounds very good, and 65 pounds ideal. If the delivery system in your town has less than 45 pounds, your RO unit will probably be somewhat inefficient. In most areas throughout North America an RO system can be considered a worthwhile investment.

Deionization

Specifically tuned resins are used in DI units instead of membranes. These resins attract unwanted compounds and elements'; thereby selectively removing them from the water that passes through them. There are two different types of deionization units. One contains a mixed bed of both anion and cation resins in a single container. The other contains separate beds of each type resin each in its own container. Anion resin filters out negatively charged ions and cation resins remove positively charged ions.

The water that passes through a DI unit is 100% usable and there is no wasted water. That might lead someone to believe an RO is not needed and a DI unit by itself would suffice. Not true! It is far better to first process water through an RO, then pass it through a DI unit because this allows the RO to remove the majority of the pollutants. Otherwise the anion/cation resins would quickly clog and require either servicing or replacement. Not pleasant for your wallet or in accomplishing what is needed to regenerate resins.

The Ultimate DI

With a better understanding of the processes involved we can ask ourselves if any further water purification equipment is needed. And, if so, why? To

answer that was the reason for my visit to the SpectraPure facility.

I have been using the SpectraPure Silica Buster, a world-renowned unit that combined the best of the best RO and DI equipment. So pure was its water it was only necessary to wipe a haze of diatoms off the inside of my aquarium panels about every ten days. Not bad I thought until I was told there was going to be something much better.

How could there be something better I asked? I was informed that when water passes through an RO its pH is reduced to the point where a certain type silica removal becomes impossible by the resins in DI cartridges. News to me! Yet, I have always wondered why diatoms started to form in about five days after a water change. Of course, processed water made their presence much less, but did not eliminate them from reforming on aquarium inside panels in the coming days. Not until now!

Now bear in mind that every RO unit reduces the pH of its product water. When pH is reduced a silica call "colloidal" silica is not attracted by DI resins and simply stays in the resulting processed water where it eventually helps to form diatoms in the aquarium. So, in addition to whatever silica and other plant nutrients slips through the RO process the entire amount of colloidal silica in the units incoming water is also part of the RO's processed water. And "your present DI equipment will not take out this colloidal silica." Good news for those diatoms in your aquarium, not so for those that have to remove them.

The only way to get this type silica out is to boost the pH of the water coming from the RO, which no existing DI units accomplish. At least not until you own the Ultimate DI System. I installed the first test unit in my backporch filtering system by removing the existing DI cartridges at the end of my RO unit and installing this system's housing units.

The first two cartridges in the four stage Ultimate unit boost pH and remove remaining contaminates coming from the RO unit. The last two cartridges polish the water further and reduce pH back to an approximate 8.0 level.

The unit's four resin cartridges are each mounted in a clear housing. As the resin becomes exhausted in the first two cartridges it changes color. When the first cartridge changes to an orange color it should be discarded and replaced with the cartridge in the second housing. A new cartridge should then be installed in the second clear housing. This kind of visibility prevents any serious level of impurities from progressing any further. The last two housings contain mixed bed polishing resins that do not change color and further purify the water. For further quality control there is an electronic purity monitor between the last two cartridges. By pressing its test button a red or green LED is illuminated indicating the status of the water coming from the next to last cartridge. It provides the perfect way to tell when the first of these last two cartridges has to be changed. The same scheme of cartridge replacement is used as is for the first two cartridges. Overall, this guarantees that the resulting product water has a greater than 18 megohm purity.

I have been using this first test unit for eight months and the change in maintaining inside panels of my aquarium has been noticeably improved. They are still very clean at three weeks after a general wiping and only require minimum attention when I do clean them. So far I've used 800 gallons of product water and only about half of the resin has changed color in the first cartridge. At this rate I'll get well over a thousand gallons of product water before the first cartridge needs to be changed. When I called SpectraPure to discuss the results I noted that this still unnamed equipment should be called the Ultimate DI system. They agreed. If you want improved processed water, the Ultimate DI system is a must! Contact them for information on this major improvement in water processing equipment.

Bob Goemans, Ph.D.

Reference

1) SpectraPure Inc., 215 S. Industrial Drive Suite 2, Tempe, AZ 85281, USA, (800) 685-2783, (602) 894-5437, FAX (602)-894-6109, http://www.spectrapure.com/.