SeaChem's Reef Fusion 2 - 500 mL is specially formulated to supply your tank with the needed carbonates, bicarbonates and alkalinity to help your corals grow. Alkalinity is used to process calcium which helps your corals grow. Reef Fusion 2 contains a mix of carbonates and bicarbonates at an alkalinity of 4400 meq/L. When used in conjuction with Reef Fusion 1 the power system will maintain calcium and alkalinity levels.