The HI701-25 are high-quality reagents designed for use with the Free Chlorine Checker, providing fast and accurate measurements of free chlorine levels. These pre-measured reagents follow the DPD Method, where the reaction between chlorine and the reagent produces a pink tint in the sample. Simply add the HI701-25 reagent packet to your sample, and the Free Chlorine Checker will determine the concentration from the resulting color, displaying the results in ppm (mg/L) of free chlorine. With their ease of use and reliable results, the HI701-25 reagents are an essential tool for monitoring and maintaining proper chlorine levels in various applications, ensuring safety and effectiveness.