The HI95771-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. These reagents follow a method in which the reaction between chlorine and reagent causes a color tint in the sample. The intensity of color is determined by a compatible photometer and the chlorine concentration will be displayed in mg/L (ppm). These reagents are designed to be used with samples that have an expected range of 0 to 500 mg/L (ppm) total chlorine.