Tetra AquaSafe contains special compounds that eliminate chlorine and bind up heavy metals. In addition, it contains colloids that coat the fish, protecting them against infection. AquaSafe also contains stress-reducing vitamins, and compounds that inhibit bacteria and fungi. All this means that your fish are well protected against the harmful effects of tap water, and the stress of water changes. At times it is necessary to add tap water to the aquarium, as part of a water change or a top-up. Tap water 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.