The HI-711-25 are high-quality reagents that are pre-measured, allowing for users to achieve fast and accurate measurements with their Total Chlorine Checker® HC - HI-711. 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 HI-711-25 reagent to the sample, the reaction will take place and the HI-711 will determine the concentration from the colour that is produced. The results will be displayed in ppm (mg/L) of total chlorine. These reagents are designed to be used with samples that have an expected range of 0.00 to 3.50 ppm (mg/L) total chlorine.