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 the 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 the results to the color card. Then follow the recommendations on the card if action is required. With API Aquarium products, it’s easy to keep a beautiful saltwater, freshwater or reef aquarium.