The HI93764A-25 reagent kit contains 25 ready-to-use vials of HI93764A-0 and 1 bottle HI93764-0 Nessler reagent. These high quality reagents follow an adaptation of the ASTM Manual of Water and Environmental Technology, D1426-92, Nessler method. In this method, the reaction between ammonia and reagents causes a yellow tint in the sample. The amount of ammonia is then measured colorimetrically. The intensity of color is determined by a compatible photometer and the concentration is displayed in mg/L (ppm) of ammonia nitrogen. These reagents are designed to be used with samples that have an expected range of 0.00 to 3.00 mg/L (ppm) ammonia nitrogen.

Hanna vials contain pre-dosed reagent so the user simply needs to add a small quantity of the sample to use as the blank, followed by the addition 4 drops of the Nessler reagent to measure the concentration. With pre-dosed vials, test preparation time is dramatically reduced and there is no time-consuming reagent preparation procedure or glassware cleaning. The vials and caps of the reagents have been designed to avoid accidental reagent spills. Due to the pre-dosed reagents, the amount of chemicals and handling time is also minimized.