DIRECTIONS: For best results, PhosGuardª should be placed so as to maximize the flow of water through it. It may be used in a canister filter, box filter, or any high flow area of a trickle filter. In some situations it may be necessary to use in a filter bag. Use 250 mL (~1Êcup) for every 300 L (75 gallons*). Leave product in place for 4 days, then test phosphate or silicate concentrations with either MultiTest: Phosphateª or MultiTest: Silicateª. If the concentration of the component you are trying to decrease has not dropped to around 0.02 mg/L, then replace the PhosGuardª, otherwise leave in place until levels begin to climb again. As long as concentrations remain under control, the product is not exhausted. Each 1 L of PhosGuardª treats over 1200 L (300 gallons*) (i.e. will remove up to 60 mg/L phosphate in 1200 L (300 gallons*) of water, depending on the initial phosphate/silicate concentrations and the current biological load. Over treating is not r - UPC: 116018708