Shake well before use. Using the dosing cap, add 50 ml Tetra Pond CrystalWater per 1,000 litres of pond water. For best results, ensure the product is mixed thoroughly into the pond water. Important! Ensure that the carbonate hardness (KH) of the water is equal or higher than 6° dH prior to each use. If the level is too low, the carbonate hardness should be increased in a controlled manner using a product such as Tetra Pond WaterStabiliser. Do not use to combat algae. Use Tetra Pond AlgoRem to combat green water (suspended algae). For best results, wait four to five days between treating the algae and using Tetra Pond CrystalWater.