Calcium chloride pellet or flake supplement for dosing marine aquariums to increase calcium levels.

Calcium is one of the major ions in seawater. Its concentration in natural seawater is about 420 ppm, so it comprises just under 1.2% by weight of seawater's solids. In the ocean, variations from this concentration are most often caused by changes in salinity, which cause the calcium to fluctuate just as the salinity does. A calcium ion carries two positive charges in seawater and is written as Ca++.

Calcium is very important in a reef aquarium as many organisms, including corals and coralline algae, take it up in order to deposit calcium carbonate skeletons. If it is not maintained at adequate levels, such organisms become stressed and can even die. I recommend that reef aquarists maintain calcium at 380-450 ppm.

Price is per kilogram.