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Portable Dissolved Oxygen Meter

portable dissolved oxygen meter OX25

The OX25-K Portable Dissolved Oxygen Meter is designed to offer accurate measurement of the saturation and concentration of dissolved oxygen in process or environmental applications, whether in laboratory, field or industrial environments.

OX25-K Portable Dissolved Oxygen Meter Introduction

The OX25-K is supplied as a complete Dissolved Oxygen measuring kit complete with the OX25 conductivity meter; a dissolved oxygen sensor with an integrated temperature measuring device, for automatic temperature compensation, complete with a professional looking carrying case.

The OX25-K is supplied complete with model O23-IP3 Polarographic DO2 sensor and a separate temperature sensor (model ST11) so that dissolved oxygen readings can be initiated immediately.

The OX25-K portable dissolved oxygen meter is capable of the following ranges with the associated resolutions:-

  • 0 - 200% dissolved oxygen saturation with a resolution of 1%.
  • 0 - 19.9mg/L (ppm) with a resolution of 0.1ppm.
  • -50° to 150°C with a resolution of 0.1°C.

Please note that the automatic temperature compensation corrects from a range of 0-40°C.

The Polarographic sensor is powered from the instrument and provides accurate dissolved oxygen readings.  Automatic temperature compensation is achieved via the integrated temperature measuring devices.

The ST11 is a separate temperature measuring device which allows the instrument to show the measured temperature of the solution.

OX25-K Correction for Barometric Pressure

The OX25-K Dissolved Oxygen meter measures the partial pressure of oxygen held within the measured solution. During manufacture, the OX25-K is set-up with factory calibration to show the oxygen contents in water at a barometric pressure of 760mm / Hg or 1013 mbar.

The OX25-K is required when barometric pressure differs significantly from 1013 mbar such as at elevated altitudes. The instrument can easily be calibrated by % saturation to ensure that future readings in both % Saturation and mg / L (ppm) are correct for the reduction in barometric pressure / increase in elevation.

OX25-K Correction for Salinity

The amount of dissolved oxygen in water decreases as the salinity of the solution increases. The OX25-K is designed so that the percentage saturation of the solution automatically compensates for an increase in the salinity of the solution.

When used in mg/L (PPM) mode, the OX25-K needs to be calibrated to ensure that the measurement remains correct. We would strongly recommend measuring the conductivity of the solution to give an accurate figure for salinity in g/l.  This figure can the be used in conjuction with the % Saturation figure to give an accurate concentration measurement in mg/L according to the chart shown below:-

ConductivitySalinity (g/L)Saturation (%)
0mS 0.0 100
6mS 2.5 97
11mS 5.0 95
15mS 7.5 93
20mS 10.0 90
24mS 12.5 88
27mS 15.0 85
31mS 17.5 82
34mS 20.0 81
37mS 22.5 78
40mS 25.0 75
43mS 27.5 73
45mS 30.0 70
47mS 32.5 68
49mS 35.0 66

OX25-K Portable Dissolved Oxygen Meter Features & Benefits

The OX25-K is designed for use as a precision device enabling both quick and accurate dissolved oxygen measurements to be made.

The polarographic dissolved oxygen sensor uses an oxygen permeable membrane with platinum cathode and silver electrode separated in our electrolytic reference solution. The dissolved oxygen sensor quickly polarises so that the OX25-K is ready to begin making dissolved oxygen measurements.

The OX-25K dissolved oxygen meter comes complete with both a temperature sensor and a dissolved oxygen sensor, all supplied in a professional carrying case, making it suitable for use in field applications, industrial applications or in laboratory environments.

Easy to setup and simple to calibrate, the OX25-K can also be used where the barometric pressure may vary and is perfectly suited for use in applications where the salinity of the measured solution is variable.

OX25-K Portable Dissolved Oxygen Meter Specifications

  • Specifications


    OX25-K Portable Dissolved Oxygen Meter

    Model No:- OX25

    Dissolved Oxygen Satuation Range:- 0 – 200%

    Dissolved Oxygen Saturation Resolution:- 1%

    Dissolved Oxygen Concentration Range:- 0–19.9 mg/L

    Dissolved Oxygen Concentration Resolution:- 0.1 mg/L

    Temperature Measuring Range:- -30 to 150°C

    Temperature Resolution:- 0.1°C

    Conductivity Auto Temp Comp (ATC):- Auto 2% per ºC at a base of 25ºC

    Accuracy Dissolved Oxygen:- Saturation & Concentration modes ±2% between ±10°C of the calibrated temperature

    Temperature:- ±0.5°C

    Calibration:- 2 points

    Temperature compensation:- Automatic

    Temperature compensation Range:- 0ºC to 40°C

    Connection Type Conductivity:- Mini-Din Connector

    Operating temperature:- 0-50ºC

    Power supply:- 1 x 9v battery

    Battery Life:- > 200 Hours

    Weight:- 400 grams

  • Features


    • Portable Dissolved Oxygen meter complete with dissolved oxygen sensor with automatic temperature compensation and seperate temperature sensor.
    • The kit comes with a robust carry case with space to carry all the associated sensors.
    • Easy to setup, calibrate and take measurements.
    • Very quick polarisation time to ensure dissolved oxygen measurements can be taken almost immediately after powering the instrument.
    • Suitable for Dissolved Oxygen saturation measurements and dissolved oxygen concentration measurements. Easily calibratd for changes in altitude via barometric pressure or for changes in salinity.
    • Nice easy to use instrument with excellent battery life and low power consumption - a dependable instrument for when readings are critical
  • Data Sheets

    Data Sheets


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