DPD Chlorine Analyzer

with HydroACT Multiparameter Analyzer

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The HydroACT DPD Chlorine Analyzer provides a reliable, online measurement of free or total residual chlorine based on the industry-standard DPD colorimetric method. The sensor uses a 515nm emitted light to detect the color change when DPD (N,N-diethyl-p-phenylenediamine) reacts with the chlorine in the water. The depth of the color change (absorption of the light) is proportional to the amount of Free Chlorine and/or Total Chlorine present in the sample.

  • Expandable Sensor Inputs (e.g., pH, ORP, NTU) and I/O
  • Color Display and Data-Logging with microSD Card Download
  • Modbus or Profibus Communication
  • Sample Strainer with Automatic Flushing
  • Chemical Feed Control Capability (PID)
  • Industry-standard DPD Method
  • Stable & Reliable Performance
  • User Friendly Maintenance
  • No user calibration required

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Overview

Videos

Q & A

Specifications

Downloads

Overview

The HydroACT DPD Chlorine Analyzer provides a reliable, online measurement of free or total residual chlorine based on the industry-standard DPD colorimetric method. The sensor uses a 515nm emitted light to detect the color change when DPD (N,N-diethyl-p-phenylenediamine) reacts with the chlorine in the water. The depth of the color change (absorption of the light) is proportional to the amount of Free Chlorine and/or Total Chlorine present in the sample.

Designed for stability and ease of use, the system requires no user calibration and works right out of the box, providing excellent process control. With maintenance intervals of up to six months, and easy access to internal parts, the analyzer offers simple maintenance and dependable performance in a variety of applications.

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The Chemtrac HydroACT DPD Chlorine Analyzer is an online instrument that continuously measures free or total residual chlorine using the industry‑standard DPD colorimetric method to help maintain safe and effective disinfection.

The DPD sensor injects DPD reagent into the sample, then uses a 515 nm light source to detect the color change created when the reagent reacts with chlorine, with the color intensity proportional to the chlorine concentration.

The analyzer provides stable, reliable performance with no user calibration required, while its user‑friendly maintenance and long service intervals support excellent process control at a low operating cost.

It is designed for drinking water treatment, distribution system monitoring, wastewater applications, and dechlorination processes where accurate residual chlorine measurement is critical.

Standard features include free or total chlorine measurement (0–5 mg/L range), a pre‑mounted backboard assembly, a reagent starter kit, and alarms for sample flow and reagent level.

Optional upgrades include additional sensor inputs (such as pH, ORP, NTU), expanded I/O, Modbus or Profibus communications, data logging with microSD card download, a color display, sample strainer with automatic flushing, and PID‑based chemical feed control.

Reagents are typically replaced once per month, and a maintenance kit is used about every six months, thanks to the analyzer’s stable design and easy access to internal components.

The DPD sensor offers a 0–5 mg/L measurement range with a detection limit of 0.03 mg/L, resolution of 0.01 mg/L, and accuracy of approximately ±0.5% of the measured value or ±0.04 mg/L, whichever is greater.

Specifications

Features

Description

  • Measurements

    Free Chlorine (Model: DPD/F)
    Total Chlorine (Model: DPD/T)

  • Type

    DPD Colorimetric

  • Range

    0 – 5 mg/L

  • Detection Limit

    0.03 mg/L

  • Resolution

    0.01 mg/L

  • Accuracy

    ±<0.5% of Measured Value or ±0.04 mg/L (whichever is greater)

  • Stability

    Approx. ±1% per month

  • Wavelength

    515 nm

  • Sampling Frequency

    Variable from 2.5 to 100 minutes

  • Flow Rate

    Approx. 500 ml/min

  • Temperature Range

    34-113 F (1-45 C)

  • pH Range

    Free: 4 to 12 pH
    Total: 5 to 12 pH

  • Response Time

    T100 = Sample Frequency

  • Zero Point Adjustment

    Not Necessary

  • Interferences

    ClO2, O3 , Mn, Organochlorines

  • Backboard Dimensions

    Analyzer & Sensor:
    26.5 x 24 in (675 x 600 mm)
    Depth: 5.25 in (133 mm)
    Sensor Only:
    26.5 x 12 in (675 x 300 mm)
    Depth: 5.25 in (133 mm)

  • Reagent Interval

    Replace Once per Month

  • Maintenance Kit

    Once per 6 Months

  • Warranty

    12 months from date of purchase

HydroACT Features

HA2

HA4

HA8

  • Sensor limit*

    2

    4

    8

  • Analog output limit*

    2

    4

    8

  • Relay limit*

    4

    8

    16

  • Digital Input limit*

    4

    8

    16

  • Isolated universal I/O

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    •

  • Nema 4X/IP65

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  • Wall & panel mount

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  • Multilingual

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  • High resolution display

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  • Graphical trending

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  • On/Off threshold control

    optional

    optional

    optional

  • Advanced control (e.g. PID)

    optional

    optional

    optional

  • Color display

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  • Customizable data logs

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  • MicroSD card download

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  • Remote (Internet) access

    optional

    optional

  • PROFIBUS, Modbus

    optional

    optional

*Sensors, I/O, and relays are all optional and must be specified at time of ordering.

Downloads

Title Category Upload Date File Size Download
PDF DPD Chlorine Analyzer – Datasheet
DPD Chlorine Analyzer, HydroACT Multiparameter Analyzer Nov 25, 2025 472 KB Download
PDF

DPD Chlorine Analyzer – Datasheet

472 KB
DPD Chlorine Analyzer, HydroACT Multiparameter Analyzer
November 25, 2025
Download