In the reef aquarium, a constant high calcium level is required to promote the growth of hard corals.  This element should be supplemented regularly, since it is used up quickly by the growing corals and calcareous algae. Reef Success Calcium will not affect the pH or alkalinity (buffer capacity) of your aquarium and small amounts will raise the calcium level considerably.  This product contains only natural components in a balanced composition, which will not disturb the anion balance of the sea salt even after prolonged use.