The enclosed environment of the home reef aquarium cannot be maintained for any length of time without replenishing elements that are removed through filtration and biological activity. Water changes alone are not enough to maintain coral growth. Reef Tank Additives and Reef Trace Elements are necessary for the long-term success of a reef tank. We carry an array of quality supplements needed for the reef aquarist. If you don't see an item you are looking for, please contact us and we'll get it for you.