Phosphates are building blocks for biomolecules such as DNA, RNA and proteins and can thus stimulate growth of animals such as fish, shrimp and corals. However, frequent feeding of your animals will rapidly result in phosphate concentrations which are no longer beneficial, but rather toxic to corals and fish. Dependent on the feed used (some are high in inorganic phosphates) or the method used to remove nitrates there can be a sur plus of phosphates which requires an additional media to remove this excess of phosphates from your aquarium water. Most, commonly used, phosphate removers are based on Granular FerricOxide/Hydroxide also known as GFO. PhosR is based on the same principle, however, PhosR can be regenerated in a new and easy way.