The HI708-25 are high-quality reagents that are pre-measured, allowing for users to achieve fast and accurate measurements with their Nitrite High Range Checker^® HC. These reagents follow the Ferrous Sulfate Method in which the reaction between nitrite and reagent causes a greenish-brown tint in the sample. By simply adding the packet of HI708-25 reagent to the sample, the reaction will take place and the HI708 will determine the concentration from the color that is produced. The results will be displayed in ppm (mg/L) of nitrite. These reagents are designed to be used with samples that have an expected range of 0 to 150 ppm nitrite.