The HI 713-25 is a set of 25 phosphate reagent packets for use with the HI 713 phosphate meter.
A reaction between the reagent and phosphate in a sample causes a blue tint to appear, which is measured by the meter. The meter uses an Adaptation of the Standard Methods for the Examination of Water and Wastewater, 20th edition, Ascorbic Acid method to determine the amount of phosphate present.
