The method used for measuring chlorine residuals uses a chemical compound called DPD (N,N-Diethylparaphenylenediamine), either through the use of a chlorine comparator or photometric instrument (this provides the highest accuracy and precision for measuring chlorine residuals). This compound can be provided as a tablet or as a liquid. DPD reacts instantly to produce a red color in the presence of chlorine. The subsequent addition of potassium iodide evokes a rapid color response from the combined forms of chlorine (typically chloramines).
Reference Standard Solution, 2.0ppm 118ml, Chlorine Dioxide
QC10453
Online Residual Chlorine Analyser CLX
QC20040
Chlorine Photometer, Handheld, 0-10ppm
QC700A
Chlorine Dioxide Photometer, Handheld, 0-10ppm
QC700CD
DPD-2 Dispenser, Free Chlorine, 100 tests (5ml sample size)
QC701X
DPD-2 Dispenser, Free Chlorine, 1000 tests (5ml sample size)
QC702X
DPD-2 Dispenser, Total Chlorine, 100 tests (5ml sample size)
QC703X
DPD-2 Dispenser, Total Chlorine, 1000 tests (5ml sample size)
QC704X
Cuvettes, disposable with cap, pk/100
QC705X
Reference Standard Solution, 2.0ppm 118ml, Chlorine
QC706X
Batteries, for QC700, pk/4
QC707X
DPD-2 Dispenser, Free Chlorine, 100 tests (10ml sample size)
QC710X
DPD-2 Dispenser, Free Chlorine, 1000 tests (10ml sample size)
QC711X
DPD-2 Dispenser, Total Chlorine, 100 tests (10ml sample size)
QC712X
DPD-2 Dispenser, Total Chlorine, 1000 tests (10ml sample size)
QC713X
DPD-2 Dispenser, Free Chlorine, 100 tests (25ml sample size)
QC714X
DPD-2 Dispenser, Free Chlorine, 1000 tests (25ml sample size)
QC715X
DPD-2 Dispenser, Total Chlorine, 100 tests (25ml sample size)
QC716X