Seachem PhosGuard rapidly removes phosphate and silicate from marine and freshwater aquaria. It is not recommended for phosphate buffered freshwater. Seachem PhosGuard is highly porous for high capacity and bead-shaped for optimum water flow.Seachem PhosGuard+ removes silicate and phosphate+ spherical for optimal hydrodynamics+ irreversible binding+ economical: 100 ml treats 235 litres of aquarium waterApplication of Seachem PhosGuard:May generate heat on initial contact with water. Pre-wet by adding to a double volume of freshwater, followed by a rinse. For best results, Seachem PhosGuard should be rinsed before use and placed so as to maximize the flow of water through it but not so that it tumbles against itself in flow. It may be used in a canister filter, media chamber, box filter, or any high flow area of a trickle filter. Use of a filter bag is recommended. Use 85 mL (1/3 cup) for every 200 L saltwater or 400 L freshwater. Leave product in place for 4 days, then test phosphate o