The Hanna Instruments Marine Ammonia Checker HC (HI784) is designed to accurately and quickly determine the ammonia level in marine (saltwater) samples. The digital readout makes measurements effortless. FEATURES Simple and accurate digital test for small, trace amounts of ammonia Easier to use and more accurate than chemical test kits Dedicated to a single parameter Range: 0.00 to 2.50 ppm (mg/L) NH3 Built-in timer so you don't miss a step Ideal for: Saltwater Aquariums, Marine, and Aquaculture Applications