The HI772-26 are high-quality reagents that are pre-measured, allowing for users to achieve fast and accurate measurements with the Marine Alkalinity Checker® HC. These reagents follow the Colorimetric Method in which the reaction causes a distinctive range of colors from yellow to green to blue to develop. By simply adding the packet of HI772-26 reagent to the sample, the reaction will take place and the Marine Alkalinity Checkers will determine the concentration from the color that is produced. The results will be displayed in ppm of CaCO3 for the HI755 Checker or in dKH for the HI772 Checker . These reagents are designed to be used with samples that have an expected range of 0 to 300 ppm CaCO3 or 0.0 to 20.0 dKH.