Liquid Phosphate RemoverRapid Removal of Phosphate from Marine AquariumsEven low levels of phosphate can cause problems in marine aquariums especially reef aquariums where coral growth can be affected. Anti-Phos helps to keep the water clear and the aquarium free from unwanted algae. Anti-Phos contains lanthanum which binds to phosphate forming a solid which is removed by the filter. It does not affect the biological filter or the pH of the water. Use every time you conduct a partial water change or detect a high phosphate level.