REEF ADVANTAGE CALCIUM is an optimized mixture no caustic (pH 8.3 - 8.6) of ionic calcium designed to restore and maintain calcium levels found in natural seawater. 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 Advantage Calcium 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. Compared with water, calcium (kalkwasser), Reef advantage calcium has a caustic pH and magnesium precipitates. Used as directed not precipitate the alkaline reserve.