King British Safe Guard makes tap water safe for use in aquariums. It instantly neutralises the chlorine, chloramines and heavy metals in tap water, preventing stress and gill irritation in fish. Removes excess ammonia. King British Safe Water should be used when starting a new aquarium, when carrying out water changes or topping up the aquarium with tap water or when new fish are added to your aquarium. Suitable for tropical and goldfish aquariums.