Measures the most important aquarium levels quickly and accurately. Benefits: Tests Calcium, Carbonate Hardness (KH), Phosphate, and Nitrate Fast, easy, and accurate for precise test results Compact to store at home FollowAPI Easy Care Guideand use the REEF MASTER TEST KIT: During Regular Care When addressing Water Problem Solving issues The REEF MASTER TEST KIT tests 4 key parameters to keep reef inhabitants healthy. The kit is highly accurate and economical, and includes 7 bottles of liquid test reagent, 2 computer-calibrated, laminated color cards, 4 glass test tubes with snap-tight caps, holding tray, as well as complete, step-by-step instruction booklet, including information on how to correct unsafe water conditions.