The HI93739-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. The method is an adaptation of EPA method 340.1 and the SPADNS method. The reaction between fluoride and the reagent causes a color change in the sample. By simply adding the reagents to the sample in the correct order, the reaction will take place and Hanna’s compatible HI96739 portable photometer will determine the concentration from the color that is produced. The results will be displayed in mg/L (ppm) of fluoride. These reagents are designed to be used with samples that have an expected range of 0.0 to 20.00 mg/L fluoride.