natural filtering material consisting of small marine shells, suitable for use in a marine aquarium filter as it keeps the alkaline pH value (buffer effect) stable, maintaining it at an optimal level for the health of the fish. A product highly effective for mechanical and biological filtering especially if it is used together with PRODAC FILTERWATTE and PRODAC CLAROCAR. It can be used in a calcium reactor to guarantee the necessary calcium supply to SPS and LPS corals due to their construction.