The HI723-25 are high-quality reagents that are pre-measured, allowing for users to achieve fast and accurate measurements with their Chromium VI High Range Checker^® HC. These reagents follow the Diphenylcarbohydrazide Method in which the reaction between chromium VI and the reagent causes a purple tint in the sample. By simply adding the packet of HI723-25 reagent to the sample, the reaction will take place and the HI723 will determine the concentration from the color that is produced. The results will be displayed in ppb of chromium VI. These reagents are designed to be used with samples that have an expected range of 0 to 999 ppb chromium VI.