The HI705-25 are high-quality reagents that are pre-measured, allowing for users to achieve fast and accurate measurements with their Silica Low Range Checker® HC. These reagents follow the Heteropoly Blue Method in which the reaction between silica and reagents causes a blue tint in the sample. By simply adding 6 drops from the first reagent bottle to the sample, followed by the remaining two packets of the HI705-25 reagent set, the reaction will take place and the HI705 will determine the concentration from the color that is produced. The results will be displayed in ppm (mg/L) of silica. These reagents are designed to be used with samples that have an expected range of 0.00 to 2.00 ppm silica.