The Aquarium Pharmaceutical new Saltwater Master Test kit is a complete kit for testing marine aquarium water. Tests water four (4) different ways to protect marine fish and invertebrates from dangerous water conditions. Tests include, High Range pH, Ammonia, Nitrite and Nitrate. Highly accurate and economical. Aquarium owners have been relying on Aquarium Pharmaceuticals for easy to use, accurate and reliable liquid test kits for over 30 years. What sets the API test kits apart from the competition? A key difference is the special care API takes with accuracy of color comparison charts. Each card is computer-analyzed for accurate color rendering during printing. This results in easier and more accurate comparison between your solution and the color chart. API adds another extra by laminating the test charts assuring long life. FrogPond Aquatics sells replacement test solutions and test tubes assuring you'll get the maximum value for your investment.