The HI93758B-0 reagent kit contains 50 ready-to-use vials of HI93758V-0AH, 1 bottle of HI93758B-0 solution, and 50 packets of HI93758-0 phosphorus reagent. These high quality reagents follow an adaptation of the EPA method 365.2 and Standard Methods for the Examination of Water and Wastewater, 20^th edition, 4500-P E, ascorbic acid method. In this method, the reaction between orthophosphate and the reagent causes a blue tint in the sample. The amount of phosphorus is then measured colorimetrically. The intensity of color is determined by a compatible photometer and the concentration is displayed in mg/L (ppm) of phosphorus. These reagents are designed to be used with samples that have an expected range of 0.00 to 1.60 mg/L (ppm) phosphorus.

Hanna vials contain pre-dosed reagent so the user simply needs to add a small quantity of the sample to the vial along with a packet of the potassium persulfate reagent followed by heating 30 minutes at 150℃ and cooling, then the addition of the NaOH solution to use as the blank, followed by the addition of the powder reagent to measure the concentration. With pre-dosed vials, test preparation time is dramatically reduced and there is no time-consuming reagent preparation procedure or glassware cleaning. The vials and caps of the reagents have been designed to avoid accidental reagent spills. Due to the pre-dosed reagents, the amount of chemicals and handling time is also minimized.