Back. Hach 2125915 COD Digest Vial, High Range, 20-1500mg/L (Pack of 150) $247.00. Hach 2105569 DPD Free Chlorine Reagent Powder Pillows, 10 mL, (Pack of 100) 4.8 out of 5 stars. 68. $25.03. Hach 2106769 SulfaVer 4 Sulfate Reagent Powder Pillows, 10 mL, (Pack of 100) 5.0 out of 5 stars.