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 250 mL of PhosGuardª treats over 300 L (75 gallons*) (i.e. will remove up to 20 mg/L phosphate in 300 L (75 gallons*) of water, depending on the initial phosphate/silicate concentrations and the current biological load. Over treating is not rec - UPC: 116018609