Red Sea Supplement pack for healthy Coral growth, contains 3 x 250ml bottles each of Reef Foundation A, B & C. Reef Foundation« A Calcium and strontium complex for balanced formation of the coral skeleton. Calcium, magnesium, strontium and carbonate are the basic foundation elements of coral skeletons. All of these elements need to be available in balanced proportions for positive coral health and growth. Red Sea's Reef Foundation A contains blended salts of calcium and strontium in the ratio required by corals and is part of Red Sea's complete Reef Care Program. Reef Foundation« B Carbonate & buffer complex for balanced formation of Coral Skeleton. Calcium, magnesium, strontium and carbonate are the basic foundation elements of coral skeletons. All of these elements need to be available in balanced proportions for coral health and growth. Red Sea's Reef Foundation B is a complex of carbonate and other buffers present in seawater that maintain proper alkalinity and pH, and is part of Red Sea's complete Reef Care program. Reef Foundation« C A magnesium complex for balanced formation of coral skeletons. Calcium, magnesium, strontium and carbonate are the basic foundation elements of coral skeletons. All of these elements need to be available in balanced proportions for positive coral health and growth. Red Sea's Reef Foundation C contains blended salts of magnesium and is part of Red Sea's complete Reef Care Program.