The HI93750-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. These reagents follow an adaptation of the Tetraphenylborate method. The reaction between potassium and reagents causes turbidity in the sample. By simply adding the reagents to the sample, a 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 potassium. Based on the range selected with the meter these reagents are designed to be used with samples that have an expected concentration between 0.0 and 200 mg/L potassium for benchtop photometers and 0.0 and 100 mg/L potassium for the portable photometer. Each meter offers multiple ranges.