Supplement contains concentrated strontium. Strontium, beside calcium and magnesium, is the one most important trace elements in natural sea water where its concentration is about 8ppm. It is strongly assimilated along with calcium in both the coral skeletons and shells of marine invertebrates. According to our research ratio of Ca: Sr dissolved from calcium reactors is below normal levels taken out by corals during calcification. Additional supplementation is necessary and linked with rapid coral growth.