The HI93708-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. These reagents follow an adaptation of the Ferrous Sulfate method in which the reaction between nitrite and the reagent causes a color change in the sample. The intensity of color is determined by a compatible photometer and the concentration will be displayed in mg/L (ppm) of nitrite. These reagents are designed to be used with samples that have an expected range of 0 to 150 mg/L nitrite.