The HI93710-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. These reagents follow the Phenol Red Method in which the reagents produce a range of color that is pH-dependent. By simply adding 5 drops from the bottle of reagent to the sample, the reaction between the sample and reagent causes a tint in the sample that can vary from yellow to red. The intensity of color is determined by a compatible photometer and the concentration will be displayed. The results will be displayed in pH units with a resolution of 0.1 pH. These reagents are designed to be used with samples that have an expected range of 6.5 to 8.5 pH.