Tetra Crusta AquaSafe 100 ml, makes tap water safe for your fish. Makes tap water habitable in an instant. Harmful substances in tap water are neutralised: chlorine is eliminated: heavy metals such as copper, zinc and lead are completely and permanently neutralised. Beneficial substances are added: iodine for vitality, vitamin B for stress and magnesium for healthy moulting. Dosage for Tetra Crusta AquaSafe: Add 5ml for each 10 litres of aquarium water for new setup or during water change.