Calcium – an agent to maintain constant levels of calcium in coral reef aquaria. Dissolve 50g of the product and 10g of Magnesium Aquaforest in 1000ml of deionized water. To maintain ion equilibrium, use KH Buffer and Reef Mineral Salt Aquaforest products as well. Calcium 10g in 100l of water increases by about 60 mg / l (ppm ) calcium levels.The recommended calcium level in coral reef aquaria is 400-440 mg/L. Contains CaCl2.