The HI93751-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. The reaction between sulfate and the barium chloride reagent causes a suspension in the sample, light absorbance of the suspension can then be measured. By simply adding the reagent to the sample, this reaction will take place and a compatible benchtop or portable meter can be used to determine the concentration. The results will be displayed in mg/L (ppm) of sulfate. These reagents are designed to be used with samples that have an expected range of 0 to 150 mg/L sulfate for the portable photometer and 0 to 100 mg/L sulfate for the benchtop photometers.