DPD chlorine tablets employ DPD indicator (diethyl-p-phenylenediamine) to distinguish levels of free, combined, and total chlorine in a simple test sample
DPD chlorine tablets designated “Instrument Grade” are suitable for use with colorimeters and spectrophotometers
DPD No. 1 Tablet is used to measure free available chlorine in water. Range: 0 to 10 ppm for approximately 10 mL sample size