REEF COMPLETE is an optimized prepared concentrate (160.000mg / L) of ionic calcium designed to restore and maintain calcium to levels found in natural seawater without affecting pH. Calcium and carbonates are essential to all coral growth. If you remain deficient, coral growth will cease, followed by a rapid decline in coral health. Reef Complete also includes magnesium and strontium in amounts proportionate to typical rates of use. This allows you to keep these two important elements while maintaining calcium.