Neutralizes ammonia and nitrites that can build up in aquarium water. For fresh and saltwater aquariums. Should be used when preparing tap water for fish or high levels of ammonia are detected. Neutralizes harmful ammonia that builds up in water. Acts as a water conditioner by neutralizing chlorine and chloramines-preparing tap water for fish. For fresh and saltwater aquariums Should be used when preparing tap water Acts as a water conditioner