Red Sea Reef Foundation B KH/Alkalinity 1kg PowderCalcium, Magnesium, Strontium and Carbonate are the basic foundation elements of coral skeletons. All of these elements need to be available in balanced proportions for positive coral health and growth. Red Seas CALCIUM+ contains blended salts of Calcium and Strontium in the ratio required by corals and is part of Red Seas complete Reef Care Program. Concentration: Powder supplement: 1g will raise the Ca level of 100 liters (25 gal) by 3. 6ppm. 1 kg