Caribsea Aragamax Select Aragonite is sugar sized oolite, ideal for reef or fish tank bottom cover. It is the perfect substrate for African Rift Lake cichlids. Caribsea Aragonite buffers to the highest pH making it perfect for African Rift Lake cichlids. It helps to create a natural biological and mineral balance to discourage nuisance algae growth and maintain the health of your fish and inverts. Aragonite delivers more calcium, carbonate and trace elements than any other substrate, keeping your aquarium healthier for longer. It is collected from pristine ocean waters with no harmful tar, organics or impurities. It may be rinsed but this is not a requirement. It is an aid to your biological filtration because it controls nitrite, ammonia and other wastes. It is ideal for shallow beds and reef bottom cover.