Tetra 250ml Easy BalanceTetra Easy Balance reduces the need for frequent water changes by creating and maintaining a healthy balanced environment. Add to the aquarium at a rate of 2. 5ml per 10litres (2 gallons) every week to replace regular water changes. Perform a 50% water change using tap water conditioned with AquaSafe at least once every 6 months. When using EasyBalance ensure that the aquarium is properly aerated. EasyBalance is only suitable for use in mature tanks