This reagent kit for free chlorine, 0 to 2.5ppm, comes in sachets which are pre-measured to allow the user to achieve fast and accurate measurements. These reagents pair with the Hanna Pocket Colorimeter HI701. The method to go with these reagents is the DPD method, where the reaction between chlorine and reagent causes a pink tint. The results will be displayed in ppm of free chlorine.