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). Carbonate Hardness/Alkalinity Profi-Test: * Calcium is not the only substance needed to form the skeletal material of corals and allow calcareous algae to grow. Carbonate and bicarbonate are also needed and these two substances can have a major effect on stabilising or buffering pH levels in the aquarium in the correct range of 8.1 to 8.4. * The total carbonate and bicarbonate concentration is also called alkalinity or carbonate hardness and for a stable system the alkalinity should not fluctuate by more than 5% from the optimum level of approx. 2.8 meq/L i.e a maximum fluctuation of 0.14 meq/L. * The Salifert test is sensitive enough to detect small changes in levels of alkalinity, measuring in steps of 0.1 meq/L and demonstrating a very sharp colour change. * The Salifert KH + pH buffer additive makes correction of the alkalinity or carbonate hardness simple and does not upset the pH of the system * Sufficient for 100 to 200 tests.