Calcium is necessary for the growth of hard corals, soft corals and other invertebrates. As calcium is depleted in reef aquariums, supplements is vital for the growth and flourish of corals and palys a crutial role maintaning high pH needed in marine systems. Direction for Use: Premix the Bio Calcium Supplement totally into the water to be added. Calculate the aquarium water volume, and add the Bio Calcium according to the volume of aquarium water. A level of measuring spoon can measure Bio Calcium Supplement approximately 9 g/0.32 oz which can mix in 100 L/25 U.S.gallon water. This will raise Calcium of 60ppm. Maximum dosage of Bio Calcium Supplement don't recommended over than 50ppm for each time. Caution: Please don't directly add the Bio Calcium Supplement to your tank. To aviod the stress reaction of marine animals, recommend to premix Bio Calcium totally before adding.