The HI93705-03 are high quality reagents that are pre-measured, allowing for users to achieve fast and accurate colorimetric measurements. These reagents follow the ASTM D859 heteropoly blue method in which the reaction between Silica and the reagent causes a blue tint in the sample. By simply adding the reagents to the sample in the correct order, the reaction will take place and one of Hanna’s compatible benchtop or portable meters will determine the concentration from the color that is produced. The results will be displayed in mg/L (ppm) of Silica. These reagents are designed to be used with samples that have an expected range of 0.00 to 2.00 mg/L Silica.