Home test kits with pH adjusters are also available. Ammonia Ammonia poisoning, the leading cause of fish loss, is most likely to occur at toxic levels in a newly established tank where the process of biological filtration has not been established, in an old aquarium where the pH has become alkaline, or in an over-crowded tank. Ammonia, which destroys the mucus membranes of fish, is secreted by fish directly through the gills as a waste product, and by the bacterial breakdown of fish waste, uneaten food and plant by-products. This causes the ammonia levels in the tank to reach toxic levels, known as ammonia poisoning. Adequate and proper filtration, and regular water testing, help keep toxic ammonia levels from occurring.
Products are also available to help keep ammonia levels in check.
Ammonia can be removed by using a liquid ammonia remover that is placed directly in the water, or ammonia chips, which are put into your canister or power filter. Water Hardness Water hardness refers to the amount of calcium and magnesium salts present in the water. Too much hard water causes a white crust to form on parts of the aquarium. Hard water makes it difficult to adjust the pH. Products are available to help soften the water. Nitrites and Nitrates Nitrites are converted by beneficial bacteria into nitrates.