Measure the most important reef aquarium levels including calcium, carbonate hardness (KH), phosphate and nitrate with API REEF MASTER TEST KIT. Proper balance is key to the overall health of reef inhabitants. Corals and reef invertebrates like shrimp, crabs and encrusting algae require calcium to grow and proper levels of carbonate hardness to prevent harmful fluctuations in pH. Excess phosphate, which comes from fish waste, uneaten food and other decaying organic matter as well as tap water, can cause algae blooms and affect healthy growth of hard corals. High nitrate levels from fish waste and organic compounds can cause fish disease and algae blooms. The API REEF MASTER TEST KIT comes with four different tests that are specifically calibrated to measure these levels in reef aquariums. Just fill the test tubes, add the test drops and compare results to the color card. Then follow the recommendations on the card if action is required. With API aquarium products, its easy to keep a beautiful saltwater, freshwater or reef aquarium. For almost 60 years API has developed premium solutions with proven and effective results for your family and ours. API offers a range of testing kits, water conditioners, and nutritionally superior food, because were dedicated to making a better underwater world. They work to provide a safe, hospitable environment for fish such as tropical community fish, cichlids, goldfish and more. At API, we understand the rewards and relaxation of fishkeeping because we have a passion for fish too.