how often should i feed my siamese fighting fishThis will add the salts that rainwater doesn’t have. It also will neutralise some but not all the possible contaminants. Mains WaterIf you are in a neighborhood with Chlorinated water, a water conditioner will get rid of the Chlorine. In areras which use Chloramine, ther conditioner will still work, but needs to be used at up to five times the traditional rate. If the Ph of the water is adjusted to be lower than 7. 2 the ammonia from the Chloramine aren’t be dangerous.