Inland Seas Marine & Reef Activated Carbon is a premium pelletized activated carbon. Carbon is used to purify aquarium water by removing dissolved organics, medications, and yellowing compounds. Inland Seas Marine & Reef Activated Carbon is a bituminous coal based pelletized carbon.. This carbon has a wide range of micropores and macropores for superior removal of both small and large compounds. Pelletized carbon allows optimum water flow in and around the carbon, and resists trapping of fine particles. Inland Seas Marine & Reef Activated Carbon has a high hardness value to reduce dust.