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).
![QC10453 Reference+Standard+Solution](/img/cache/qc10453-reference-standard-solution-2-250x250.jpg)
Reference Standard Solution, 2.0ppm 118ml, Chlorine Dioxide
QC10453![PS20040](/img/cache/ps20040-250x167.jpg)
Online Residual Chlorine Analyser CLX
QC20040![chlorine_pocket_photometer_case.tif](/img/cache/chlorine-pocket-photometer-casetif-250x250.jpg)
Chlorine Photometer, Handheld, 0-10ppm
QC700A![chlorine_dioxide_pocket_photometer.tif](/img/cache/chlorine-dioxide-pocket-photometertif-250x250.jpg)
Chlorine Dioxide Photometer, Handheld, 0-10ppm
QC700CD![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-150x150.jpg)
DPD-2 Dispenser, Free Chlorine, 100 tests (5ml sample size)
QC701X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-6-150x150.jpg)
DPD-2 Dispenser, Free Chlorine, 1000 tests (5ml sample size)
QC702X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-8-150x150.jpg)
DPD-2 Dispenser, Total Chlorine, 100 tests (5ml sample size)
QC703X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-7-150x150.jpg)
DPD-2 Dispenser, Total Chlorine, 1000 tests (5ml sample size)
QC704X![10431](/img/cache/10431-250x146.jpg)
Cuvettes, disposable with cap, pk/100
QC705X![QC10453 Reference+Standard+Solution](/img/cache/qc10453-reference-standard-solution-250x250.jpg)
Reference Standard Solution, 2.0ppm 118ml, Chlorine
QC706X![AA-Battries](/img/cache/aa-battries-2-250x250.jpg)
Batteries, for QC700, pk/4
QC707X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-2-150x150.jpg)
DPD-2 Dispenser, Free Chlorine, 100 tests (10ml sample size)
QC710X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-10-150x150.jpg)
DPD-2 Dispenser, Free Chlorine, 1000 tests (10ml sample size)
QC711X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-12-150x150.jpg)
DPD-2 Dispenser, Total Chlorine, 100 tests (10ml sample size)
QC712X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-14-150x150.jpg)
DPD-2 Dispenser, Total Chlorine, 1000 tests (10ml sample size)
QC713X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-3-150x150.jpg)
DPD-2 Dispenser, Free Chlorine, 100 tests (25ml sample size)
QC714X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-11-150x150.jpg)
DPD-2 Dispenser, Free Chlorine, 1000 tests (25ml sample size)
QC715X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-13-150x150.jpg)
DPD-2 Dispenser, Total Chlorine, 100 tests (25ml sample size)
QC716X![dpd_powder_pop_dispenser.tif](/img/cache/dpd-powder-pop-dispensertif-15-150x150.jpg)