Features Rapidly removes phosphate & silicate Synthetic granular ferric oxide (GFO) Less dust and thus is easier to use than most competing GFO products Overview 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. PhosNet™ also offers less dust and thus is easier to use than most competing GFO products. Comparing Seachem Phosphate Removers Product PO 4 bound PhosGuard (Alumina Oxide) 0.87 mg/g PhosBond (GFO and Alumina Oxide hybrid) 1.19 mg/g PhosNet (GFO) 1.41 mg/g