Calcium is a major constituent of calcerious algae, skeletal material of hard corals and the skeletal needles of soft/leather corals. Calcium also fulfils many biological functions. These processes result in depletion of calcium. Often, a low calcium concentration retards growth of coral and calcareous algaes. Natural Sea Water contains 420 to 450 mg/l of calcium. This is also the value we should strive for. For a stable aquarium environment the fluctuation in calcium content should not be more than approx 15 mg/l. Salifert have highly concentrated coral calcium. In fact a higher concentration is impossible to achieve. Each liter contains approximately 160 000 mg of calcium. You will appreciate this when you consider than an average aquarium depletes 5-8 mg of calcium per liter each week. To avoid an ionic imbalance, Salifert have properly balanced the calcium with ions such as sulphate, chloride, bromide, sodium and magnesium. Directions: Shake well before use. For regular maintenance, dose 5ml per 100lts once a week. Adjust dosage according to individual requirements using an accurate Calcium test kit. Every 5ml of Coral Calcium will increase the calcium of 100lts by 8mg/l (ppm). Never increase the calcium concentration by more than 50mg/l a day. Maintain calcium concentrations of 420 to 450 mg/l.