Seachem PhosNet Phosphate and Silicate Remover
Rapidly removes phosphate and silicate. 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 capacity than most competing products and consequently can reduce phosphates and silicates to very low levels.