Salifert Profi Test Kits for reef, marine and advanced freshwater aquarists are some of the most precise and accurate test kits on the market. Kits are available for all aspects of the aquarium’s chemistry, covering organic and inorganic pollutants as well as valuable marine trace elements to allow for accurate dosing when additives are required. The kits feature bold colour changes and good colour comparison charts and offer quick and easy water testing. There are 16 kits in the range, and most are suitable for both freshwater and saltwater environments (unless otherwise stated). Calcium Profi-Test: * Calcium is a major constituent of coralline algae, the skeletal material of hard corals and the skeletal needles of soft/leather corals. In many cases too low a calcium concentration retards coral and coralline algae growth. * Calcium also fulfils many important biological functions. * In a healthy aquarium, the growth and multiplication of corals, calcareous algae and other organisms can result in calcium depletion. To maintain a stable environment it is important that the calcium content should not fluctuate by more than 15 mg/L from the optimum range of 420 – 450 mg/L so regular testing should be carried out. * This means that any calcium test used should have an accuracy of significantly less than 15mg/L otherwise it will be difficult to monitor such fluctuations. * The Salifert test kit measures in steps of 5 mg/L and has an accuracy of 10 mg/L. * The colour change is precise, detecting small but significant fluctuations in the concentration of calcium. * The test is not affected by magnesium. * Salifert’s Coral Calcium additive is a highly concentrated additive which makes calcium addition easy. * Sufficient for at least 50 tests.