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![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)