The HI93701-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. These reagents follow the DPD Method in which the reaction between chlorine and reagent causes a pink tint in the sample. By simply adding the packet of HI93701-03 reagent to the sample, the reaction will take place and one of Hanna’s compatible benchtop or portable meter will determine the concentration from the color that is produced. The results will be displayed in mg/L (ppm) of free chlorine. These reagents are designed to be used with samples that have an expected range of 0.00 to 5.00 mg/L free chlorine.