The HI-764-25 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate measurements with their Nitrite Ultra Low Range Checker® HC. These reagents follow the Diazotization Method in which the reaction between nitrite and reagent causes a pink tint in the sample. By simply adding the packet of HI-764-25 reagent to the sample, the reaction will take place and the HI-764 will determine the concentration from the colour that is produced. The results will be displayed in ppb of nitrite. These reagents are designed to be used with samples that have an expected range of 0 to 200 ppb nitrite.