Seachem PhosNet is a granular ferric oxide (GFO) with high porosity, high surface area and high binding capacity. It will rapidly remove phosphates and silicates from both freshwater and saltwater and will not release them back into your aquarium. It exhibits stronger binding than most competing products and consequently can reduce phosphates and silicates to very low levels. Seachem PhosNet also offers less dust and thus is easier to use than most competing GFO products.Use of SeachemPhosNetFor best results, Seachem PhosNet 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. The 100 ml comes with net bag.Use 50 g of Seachem PhosBond for every 200 L saltwater or 400 L freshwater. Leave product in place for 4 days, then test phosphate or silicate concentrations.