To treat clouding, add 5 ml per 10 litres of aquarium water. Add 2.5 ml per 10 litres if the KH value is below 3°dH. Wait for at least 48 hours between applications. After using a water conditioner such as Tetra AquaSafe, wait for 24 hours before using Tetra CrystalWater. The filter should be cleaned regularly for optimum results. Note: When the product takes effect, the active ingredients release a white cloud that is harmless and disperses within a few hours.