The HI93715-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. These reagents follow the Nessler Method in which the reaction between ammonia and the reagent causes a color change in the sample. The intensity of color is determined by a compatible photometer and the concentration and based upon the meter will be displayed in mg/L (ppm) as ammonia (NH₃) or ammonia nitrogen (NH₃-N). These reagents are designed to be used with samples that have an expected range of 0.00 to 9.99 mg/L ammonia.