Reef Building Supplement for Corallin Algae, Corals, Clams, & Other Marine Invertebrates Overview Complete source of the elements and molecules directly used by corals, clams, and other reef-building invertebrates and organisms to create skeletal material and grow. Provides calcium, strontium, magnesium, and potassium in approximately the same ratios in which they occur in aragonite, the mineral that is primarily secreted by reef-building marine organisms under normal environmental conditions. Very strong source of carbonates, also involved in aragonite formation; twice the calcium relative to carbonates compared to natural aragonite. Formulated by a marine scientist.