AquaCleanse is used to eliminate common chemicals in tapwater that are toxic to fish and other pond creatures. These chemicals, such as chlorine, chloramines and ammonia, are in tapwater in order to make it safe for us to drink by killing bacteria, viruses and parasites. However, these same chemicals can also kill your fish which is why you need to add AquaCleanse to your tapwater before setting-up a new pond and doing routine water changes. AquaCleanse destroys the chemical bonds that form ammonia, chlorine and chloramines. AquaCleanse has no unpleasant sulfide odors. For Koi Pond & Water Gardens.