Chlorine and Chloramines
Chlorine and chloramines are harmful to fish and will kill the beneficial nitrifying bacteria in the pond. Likewise, they may burn or kill aquatic plants. Chlorine, a volatile gas, will dissipate with water circulation and exposure to the air within one or two days.
Chloramines, however, take much longer to break down. City water suppliers are more frequently adding ammonia to combine with chlorine to produce the longer-lasting chloramines. It is not uncommon for city water to test positive for ammonia straight out of the tap.
When adding chlorinated water to the pond, spray it in with a hose to provide the necessary aeration for dissipation of the gas.
Make sure to use a test kit to monitor your ammonia levels carefully. High ammonia levels cause disease and death.
Run-off water from a nearby stream or collected rainwater may contain toxic insecticides, herbicides, or fertilizers. Rainwater from metal roofs or asbestos shingles will contaminate the pond and may prove toxic to both the fish, and the plants. If the fish display signs of toxicity, execute a 50% water change and/or remove the fish to safe quarters, or a hospital tank until the water has been changed.
The pH range of 6 to 8.5 is acceptable for most pond life. The primary concern with pH is its direct relationship to the toxicity of ammonia and nitrite. Each pH integer above the neutral 7 reflects a tenfold increase in such toxicities.
Any pH value below the neutral 7 is considered acidic. Baking soda or ground limestone will raise the pH level.
pH values over 8.5 will definitely stress the fish to the point of disease. We receive some calls where the pond owner claims to have a pH reading of 9.0 or more, and the cause for this is cement or mortar leeching toxic lime into the water.
Adding Salt to Your Pond
Salt is pretty amazing in its ability to control algae, detoxify Nitrites, kill parasites, and its antiseptic qualities. Salt is a great item to use for your water quality, but first… you need to know how much to add. We feel that a 0.1% continual salt bath is a good level to run at all the time. To achieve this level, add 1¼ ounces of salt per 10 gallons of pond water.
The maximum level of salt that you can run without major damage to the fish is 0.3%. This high salt level is used for treating fish wounds and parasites. To achieve this level, add 3.8 oz. of salt per 10 gallons. This salt level is better suited for a bath, or in a hospital tank.