Marine Phosphate Ultra Low Range Colorimeter – Checker HI774Brand: Hanna Instruments Features: Easier to use and more accurate than chemical test kits Dedicated to a single parameter Accuracy 0. 02 ppm 5% of reading Range 0. 00 to 0. 90 ppm Includes reagent starter kit for 10 tests Details: The HI774 Ultra Low Range Phosphate Checker HC (Handheld Colorimeter) is a cost effective way to measure phosphate in marine systems, including reef tanks. Testing for phosphates is standard practice for saltwater aquariums