Tropic Marin Bio-Calcium Enables the addition of biologically ideal calcium to the reef aquarium: All calcareous animals, especially corals need calcium and carbonates to grow and flourish. However the growth rate of corals depends mostly on the zooxanthellae (algae) that live symbiotically within them. These algae present the coral with precious carbohydrates of their own metabolism. As they photosynthesize, they use carbon dioxide from the water, which enables the coral to precipitate calcium carbonate in its skeleton. Only when calcium and carbon dioxide are available together can this symbiotic relationship work. Tropic Marin Bio-Calcium is the ideal source of both calcium carbonate for the corals and carbon dioxide for the zooxanthellae. Many calcium supplements add undesirable by-products to the water, or like Kalkwasser, influence pH. When Tropic Marin Bio-Calcium is dissolved in the aquarium, all 70 trace elements are added and no unnatural by-products are formed. Tropic Marin Bio-Calcium will not alter the pH level if used in accordance with the instructions. Natural sea water contains on average 400-410 ppm of calcium and is typically saturated at this level. It is important not to exceed 450 ppm, as super saturation can result in the calcium surplus precipitating out of the solution, taking desirable trace elements with it. We recommend the use of a Tropic Marin calcium test kit and Tropic Marin Bio-Calcium to ensure these proper calcium levels. How to Use BIO-CALCIUM: Calculate the total system water volume, being sure to take into account volume of live rock, external filters and sumps. Each level measuring spoonful (5 ml) raises the calcium level of 5 gallons (US)/4 gallons (Imp) of system water by 28 ppm. Maximum recommended dose is one level scoop for each 5 gallons (US) / 4 gallons (Imp) of tank water per day.