Julian Sprung's Two Little Fishies PhosBan is a highly porous super absorbent granular filter media made from ferric oxide hydroxide. Designed for use in Phosban Reactors; but can be used in other reactors and applications. PhosBan binds so much phosphate that it can effectively keep phosphate levels in aquariums low for months. It is ideal for use in marine; reef aquariums; and freshwater aquariums. PhosBan gives long-lasting control of phosphate levels for a clean aquarium and enhanced growth of hard and soft corals and can help control algae problems. For more information on controlling phosphates; please see our article How to Get Rid of Algae and our That Fish Blog post: Phosphates i ½ Invisible Troublemakers in Ponds and Aquariums.