A Reverse Osmosis Method For Aquariums

I should start out by stating that I am not an exotic fish expert by any stretch, but I do know a bit about water.

While this article will not deal with drinking water treatment, fish aquarium water still requires some type of treatment and often times the equipment we have available on the web site works great for aquariums that require special water.

I have fielded many phone calls from people with aquariums that are interested in reverse osmosis and activated carbon filtration. Some "aquarium people" as I'll refer to them from this point, require pure water to begin building an inhabitable and even thriving environment for their tropical fish. Most of these fish require salt water as well and from what I hear, reverse osmosis product water is the best way to start.

If the water to be treated comes from a tap (and the majority of it does) then there is a very real possibility of the presence of chlorine, which the fish cannot tolerate. The chlorine needs to be removed or rendered inert. The best way to treat chlorine economically is with activated carbon either in a filter cartridge form (which is the least expensive and most popular) or through a whole house filtration system. So with the chlorine removed or inert, the next step is to purify the water and reverse osmosis is the best way to accomplish that. So which reverse osmosis system is the best for aquarium people to use?

Well, obviously the large volume systems like the GE Merlin will not be the first choice because of their cost and because they produce ½ gallon per minute which is way more than anyone will need to fill a 100 or 200 gallon aquarium every month or so. So I usually recommend one of the low cost, low volume and inexpensive systems as a first choice. The Nelsen RO is the first one that comes to mind but the Microline is a very fine quality system that will produce and store pure water with low maintenance and the availability of a carbon/sediment dual purpose pre-filter for locations treating chlorinated water. While all reverse osmosis systems have carbon filter pre- treatment, the availability of the carbon/sediment cartridge for the Microline systems provide higher confidence that the chlorinated water is not reaching the sensitive membrane.

Now to pH balance the water. Reverse osmosis will raise the pH balance of input water. How much, you ask? It is difficult to say. On a nearly perfect balance pH water supply (7.2 to 7.4) the RO treated water will come out around 8.0. I am told that the "fishies" like balanced pH so a chemical is going to need to be added to input water that is already balanced to bring the pH down to acceptable levels.

The only other consideration that I've been told pertains to salt water fish. Apparently a salt solution or mixture can be purchased from pet stores that cater to tropical fish, but I would suggest dissolving salt in RO purified water to the point of saturation or "brine". Once your aquarium is nearly full of the non-salted reverse osmosis water, add measured amounts of this brine solution to the tank and take your salt-water readings. Once the proper balance is achieved, you should be all set.

All of this leads me to wonder; if aquarium people are willing to go to all this trouble for the water that their fish swim in, why are they unwilling to treat the water they themselves consume? Why not just get a reverse osmosis system, connect a refrigerator kit to it (just because that's the name, doesn't mean that's how it has to be connected) and run a line with a shut-off valve to the vicinity of the aquarium? That way when it comes time to deal with changing the water in the tank, everything is in place and there are very few obstacles to overcome. The fish are happy AND you're now drinking clean, healthy water right from your kitchen!