(This is a follow-up letter from Bruce Gallo.)
HI TOM,
Starting the wheels a turning on my 180-gallon tank!!! because of a septic system, and not a sewer, I can't use an RO system (too much waste water). I would never ask you to endorse manufactured products, so could you in your opinion tell me what units you have had good luck with? ... TOM I CANT THANK YOU ENOUGH FOR THE TIME AND ADVICE.
Bruce Gallo
Bruce,
First, not everybody MUST use RO (Reverse Osmosis) or DI (Deionized) filtered water. Some areas have good enough quality tap water that aquarists in those areas just use the tap water from their public water source or wells without RO or DI filtration before using it to mix up saltwater for their aquaria. Their water may still be high in TDS (total dissolved solids), mostly from calcium, magnesium and other elements that are also found in ocean water. Their tap water does not have the most harmful elements or pollutants in any harmful amounts. One such aquarist had great success using city water that he just ran through a carbon filter. He did this for well over 25 years, and then all of a sudden the water company changed additives and started putting stuff in the water that nearly wiped out his reef aquarium! I have heard of other cases also. Water companies may start adding copper sulphate to control algae or zinc phosphate to remove lead from your drinking water, or maybe other additives, at any time without notifying you. These products can wipe out a reef aquarium or at least make your inhabitants sickly at best. High levels of copper and zinc are invertebrate killers, even though VERY small trace amounts are considered essential. Phosphates and silicates are also necessary for your tank inhabitants, but NOT in the high amounts that exist in many sources of tap water! These can give your tank bad algae blooms and could slow growth of some things also!
If others in your area have been successfully using de-chlorinated tap water (maybe even carbon filtered), then you too might be safe. But, I wouldn't use just plain tap water this way unless you are positively sure that you can trust your water source.
On the other hand, one hobbyist wrote to me saying that the reef aquarists in her area could not knock out hair algae with any method except for using very pure water for mixing saltwater for filling the tank, doing water changes and for replacement (top off) water in their reef tanks - always. She said that they had found that they had to use ONLY very pure distilled water that was distilled without using copper tubing (this can add copper to the distilled water). She said that they had to do this in order to keep hair algae from growing in their reef of their reef tanks. It may sound strange to some people who have not had this problem to this extent, but the source of water that you use can have an effect on hair algae and the health of your reef aquarium in general. There are also other factors too, which can cause or add to hair algae problems. Some aquarists feel that this is a very important area to start with in the war on hair algae.
Since you are concerned about your water source you might check with your water company to see what's in it. They can give you a free water quality report, listing the concentration of many elements and toxic compounds. If it looks like you would benefit from more pure water then I would personally call or write to Spectra Pure (the biggest supplier of RO and DI units for aquarium use) and tell them about the excess water problem with your septic system which might not be able to handle all the extra waste water when using normal RO with a 1:4 or 1:5 filtered RO to wastewater ratio. Spectra Pure is run by reef aquarists who understand what our reef aquariums need from RO and DI filtration. They have good products. I am now using the 50 gpd (gallon per day) RO/DI multi stage filtration unit with pressure and purity monitors. I like it! I do not always use a DI cartridge with the RO. It works better (higher purity and better silicate removal) than my previous RO unit did. Spectra Pure can provide you with RO units that produce a 1:1 pure water to waste ratio, but they are not quite as efficient this way, but still very useful. They still remove most of the TDS (total dissolved solids) from your tap water. The higher waste water ratio improves purity with RO units. Higher water pressure going through the RO filter also produces higher purity filtered water. Colder water also produces higher purity water. But, at the same time, cold water slows down the filtration process.
If you buy an RO unit with a deionizer (in-line DI filter used after the RO filter) you would end up with even more pure water and could probably still process several hundred gallons of very pure water with each DI cartridge change, even with the low waste water ratio. Or, you could probably do pretty well with just the 1:1 RO unit and no DI if your water source isn't too bad already - no excess copper, phosphate or silicate... My 50 gpd Spectra Pure RO unit (without the DI cartridge installed) removes over 98% of the TDS from my. But, using the DI cartridge to re-filter the RO water will just polish off the remaining little bit of impurities that the RO did not remove, for the most part. The only problem with using DI without putting your water through an RO filter first is that you have NOT knocked out the worst of the dissolved solids. This means that the DI unit now has to adsorb all the dissolved solids from your "raw" tap water. This would use up my particular DI cartridges over 50 times faster than when I filter the water through the RO first and then through the DI unit last! Some areas have softer water with low TDS and CAN use DI units without RO first, without this waste. There are larger rechargeable DI units, and I think Spectra Pure has those too, but may not push them because they are not as effective or efficient as the disposable "Silica Buster" DI units. If you want the very cleanest water then don't get a rechargeable DI unit.
I have also tried a Tap Water Purifier (TWP) from Aquarium Pharmaceuticals. The TWP only produces a little over 15 gallons of purified water at my house with the moderately high TDS in my area's water source. However, when I run my water through an RO unit first and then through the TWP then it cleans well over 500 gallons of water before the color of the DI resins change, indicating exhaustion. I used to press fit the pure water outlet hose from my RO filter into the inlet hose of the TWP. A few areas have such low TDS in their tap water that they might get as much as 50 - 150 gallons of pretty pure water with one cartridge of the TWP. Call your water company to get the TDS of your tap water. A TDS level below 20 ppm (parts per million) might give you over 100 gallons of purified tapwater with the TWP unit. I have about 150 - 200 ppm TDS which is fairly typical for a lot of areas. The TWP is not as efficient as the Silica Buster in removing silicates though, and does start leaching adsorbed silicates back out into your pure water before the color of the DI beads have all changed color, indicating exhaustion. I've done some of my own testing for silicates and phosphates with the filters I mentioned above, so I'm not JUST relying on the words of a company trying to sell you and me on their products. The Spectra Pure units tested best for me. You can find the Spectra Pure address and phone numbers in their advertisements in "fish" magazines like FAMA.
Tanks-
Tom Miller