The HI93757-01 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 Standard Methods for the Examination of Water and Wastewater, 20th edition, DPD method in which the reaction between ozone and reagent causes a pink tint in the sample. By simply adding the reagent to the sample, a reaction will take place and a compatible benchtop meter can be used to determine the concentration from the color that is produced. The results will be displayed in mg/L (ppm) of ozone. These reagents are designed to be used with samples that have an expected range of 0.00 to 2.00 mg/L ozone.