Dissolved Oxygen Monitor

with HydroACT Multiparameter Analyzer

touchscreen hi-res Color Display

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The Chemtrac DO Probe is the first of its kind in the world to offer automatic in-situ sensor verification as an option. The HydroACT 300 is able to reduce maintenance by automatically checking its sensor operation at user-defined time intervals. Calibration on the In-Situ sensor is normally required only once per annum so with the automatic sensor verification option and the self-clean option the sensor may not need to be inspected at all for a full year.

  • Automatic cleaning
  • Automatic in-situ verification
  • PID control
  • No reagents or moving parts
  • Low purchase and ownership cost
  • Up to 3 sensors
  • No maintenance or calibration for up to 12 months

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Overview

Principal of Operation
The sensing element (lumiphore) is activated or excited when illuminated with a blue light. When activated, the lumiphore emits red light in an intensity that is inversely proportional to the amount of oxygen present in the water. There is also a time delay between the peak emission of blue light and peak response of fluoresced red light. The amount of delay is inversely proportional to the amount of oxygen present. This time delay can be expressed as a phase shift between the wave patterns of incident blue light and the fluoresced red light. This is in turn reported by the electronics into a ppm or mg/l reading of Dissolved Oxygen. The advantages of this technology are that it is more stable than traditional electrochemical devices and far more resistant to abrasion. By using the state of the art sensor and electronics together the reliability, accuracy, and flexibility of the HydroACT 300 with DO Probe is far superior to that of its competitors.
In addition to the state of the art optical sensor the HydroACT 300 offers Modbus communications (TCP/IP, RS485), Relays and 4-20mA outputs. Despite all of the additional functionality that this unit has to offer, the purchase costs are less than or comparable to, its competitors. Added to the cost savings of a truly automatic sensor verification system, some will achieve a replacement payback of only a few months. Also available are Dual and Triple Validation options and various PID control functions.

Automatic Sensor Verification
The Chemtrac DO Probe is the first of its kind in the world to offer automatic in-situ sensor verification as an option. The HydroACT 300 is able to reduce maintenance by automatically checking its sensor operation at user defined time intervals. Calibration on the In-Situ sensor is normally required only once per annum so with the automatic sensor verification option and the self clean option the sensor may not need to be inspected at all for a full year.

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Q & A’s

The Chemtrac Dissolved Oxygen Monitor is used to measure the concentration of dissolved oxygen in water, which is essential for various water treatment processes.

It uses an optical sensor that emits blue light to activate a lumiphore, which then emits red light. The intensity of the red light is inversely proportional to the amount of dissolved oxygen present.

Typically, manual calibration is required every 3 to 12 months, and the lumiphore should be changed annually.

The monitor measures dissolved oxygen in the range of 0-20 mg/L or 0-450% saturation.

The accuracy is ±0.1% mg/L from 0 to 8 mg/L and ±0.2% mg/L from 8 to 20 mg/L.

The monitor offers Modbus communications (TCP/IP, RS485), relays, and 4-20 mA outputs.

The response time is T90 = 30 seconds and T95 = 37 seconds.

It operates effectively in a temperature range of 0 to 50°C and a salinity range of 0 to 42 PSU.

Specifications

Features

Description

  • Type

    Lumiphore optical dissolved oxygen

  • Measured

    Dissolved Oxygen

  • Range

    0-20 mg/l or 0 – 450% Saturation

  • Resolution

    0.01 mg/l

  • Accuracy and Precision

    ±0.1% mg/l from 0 – 8 mg/l and
    ±0.2% mg/l from 8 – 20 mg/l

  • Stability

    Better than 1% per month (without calibration)

  • Salinity Range

    0 – 42 PSU (As reference: Seawater is typically 33-37 PSU)

  • Temperature Range

    > 0 up to 50° C

  • Temperature Compensation

    Automatically by integrated thermistor (ATC)

  • pH Range

    pH 2 up to pH 10

  • Permissible Over-Pressure

    7.25 psi (0.5 bar)

  • Typical Response Limit

    >25 mg/l

  • Response Time

    Not necessary

  • Calibration

    Manual using water saturated air or automatic

  • Housing Material

    PVC, silicone, polycarbonate, stainless steel

  • Dimensions

    Diameter approx. 1.72 in. OD, length 7.99 in.

  • Maintenance Intervals

    Manual calibration 3 – 12 months
    Lumiphore change 12 months

  • Interferences

    High levels of Hypochlorite

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

  • Nema 4X/IP65

  • Wall & panel mount

  • Multilingual

  • High resolution display

  • Graphical trending

  • On/Off threshold control

    optional

    optional

    optional

  • Advanced control (e.g. PID)

    optional

    optional

    optional

  • Color display

  • Customizable data logs

  • MicroSD card download

  • 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 HydroACT 4 Dissolved Oxygen Operations Manual
Disinfectant Analyzers (Chlorine, Ozone, etc.), Dissolved Oxygen, HydroACT Multiparameter Analyzer Nov 3, 2025 5 MB Download
PDF Dissolved Oxygen Monitor – Datasheet
Disinfectant Analyzers (Chlorine, Ozone, etc.), Dissolved Oxygen, HydroACT Multiparameter Analyzer Oct 29, 2025 688 KB Download
PDF

HydroACT 4 Dissolved Oxygen Operations Manual

5 MB
Disinfectant Analyzers (Chlorine, Ozone, etc.), Dissolved Oxygen, HydroACT Multiparameter Analyzer
November 3, 2025
PDF

Dissolved Oxygen Monitor – Datasheet

688 KB
Disinfectant Analyzers (Chlorine, Ozone, etc.), Dissolved Oxygen, HydroACT Multiparameter Analyzer
October 29, 2025