The HI700-25 are high-quality reagents that are pre-measured, allowing users to achieve fast and accurate measurements with their Ammonia Checker® HC. These reagents follow the Nessler Method in which the reaction between ammonia and reagents causes a yellow tint in the sample. By simply adding 4 drops from each bottle of HI700-25 reagent set to the sample, the reaction will take place and the HI700 will determine the concentration from the color that is produced. The results will be displayed in ppm (mg/L) of ammonia-nitrogen (NH3-N). These reagents are designed to be used with samples that have an expected range of 0.00 to 3.00 ppm ammonia-nitrogen. To convert the reading to ppm of ammonia (NH3) multiply the result by 1.214.