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).
![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![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)