Tetra Aquasafe 500ml neutralises harmful chlorine, cholramine and heavy metals. Supports protective mucous layers. Creates clear water. Tetra Aquasafe is suitable for Tropical & Gold fish aquariums. At times it is necessary to add tap water to the aquarium, as part of a water change or a top-up. Tap water is designed for human use, and therefore contains high levels of chlorine to kill germs. In addition, it may contain varying levels of toxic heavy metals. Both chlorine and heavy metals are toxic to fish, and will cause them long-term damage and stress. Tetra AquaSafe works by instantly neutralising these harmful substances and should be used every time new water is added to the aquarium. In addition, AquaSafe also reduces stress, promotes wound healing and protects against infection, and adds a protective coating to the fish. How to Use Tetra Aquasafe: Add AquaSafe to new tap water at a rate of 5ml per 10litres (2 gallons) to make it safe. Tetra Aqua Safe can also be added directly to the aquarium at the same dosage, to act as a general stress-reliever. When preparing tap water for water changes in the aquarium, it is best to treat it with AquaSafe in a bucket beforehand, and use boiled tap water to warm it to the same temperature as the aquarium.