By Donna M. Recktenwalt
Every aquarist knows what it is. Or do we?
Good water is a cornerstone of successful fishkeeping, along with adequate and appropriate food, proper lighting, the correct temperatures, and surroundings in which the fish feel comfortable. Only when all these conditions are met will the fish in our care prosper, show their best colors, and freely breed.
The concept of “good water” seems self explanatory, except that “good water” can vary considerably. Usually, good water is clear, clean, free of excessive extraneous matter and/or contaminants, and neither excessively hard nor soft, acid or base. Test kits are available that allow us to measure the water’s pH and Hardness, and to track the levels of ammonia, nitrate, and nitrite, byproducts of the nitrogen cycle and indicative of overall aquarium health.
But good water, the basis of this system, is a variable commodity. Local water supplies are not all the same, and not all fish require the same types of water. Local water conditions are dependent on the source, the treatments received (if any), the additives that may have been included during treatment to soften, stabilize and purify, and the pipes and conduits through which they run. Unfortunately, treated water that is safe for human use may result in the death of our fish, hence those products which neutralize chlorine and chloramine, among other chemicals, in water for aquarium use.
Well water can cover the full range from extremely soft to extremely hard, depending on the local aquifer.
The author’s local water, which comes from a treated municipal source, measures pH 7.0 from the tap and a comfortable medium hardness (about 180 ppm). Water of these parameters has proven suitable for most fish except the most discerning hard- or softwater species. But what comes out of your tap is not necessarily what your fish must live in. The natural cycles of the closed aquarium system eventually will result in a drop in pH, and possibly an increase in hardness.
If your local water conditions are too extreme, the water can be mixed or treated to achieve the desired parameters. The use of clean collected rainwater or of reverse osmosis water can provide a fairly easy way to soften aquarium water. Resin-containing softening “pillows” or bags of boiled peat can be added to the filter to adjust pH, or the aquarist can make “peat water” by soaking peat in an aerated container, and then adding the resulting dark colored liquid to the aquarium.
Most killifish are adaptable enough to be content with “ordinary” conditions; others require water purity that is only achieved by vigorous efforts. Whichever type you keep, remember that those partial water changes go a long way toward keeping your fish healthy and productive.
— G.C.K.A. Newsletter, May 1998