Hach DPD total chlorine reagent powder pillows for spectrophotometric and colorimetric determination of residual chlorine and chloramines in water, wastewater, estuary water and seawater. USEPA DPD Method 8167 (DOC316.53.01027), range 0.02-2.00 mg/L Cl₂. USEPA accepted for reporting for drinking and wastewater analyses. 25 mL sample volume, pack of 100.