Robust, Accurate, Stable and Easy to Maintain

Oxygen Probe

Dryden Aqua is the leading manufacturer of galvanic dissolved oxygen probes in the UK. Our probes are used by most of the aquaculture industry in Scotland, Norway and in many other countries around the world

The Dryden oxygen probe is a very high performance and extremely robust oxygen probe for the measurement of oxygen in water and air. The probe provides for a low cost, easy maintenance sensor suitable for connection to Dryden Aqua monitors, or your own instrumentation. Our probe is accurate down to 10ppb (0.01mg/l), and is as stable and as accurate as an optical probe but at a fraction of the cost. Also with the Dryden Aqua probe, there is virtually no maintenance cost, but with optical probes, you have an annual cap cost that is almost as much as our dissolved oxygen probe.

The probe has a high mv out-put for PLC based controllers, the high out-put increases accuracy and reduces electrical noise problems.

The unique shape provides a streamlined approach and minimizes water increases accuracy.

Typical Applications

  • Aquaculture
  • Rivers and lakes
  • Sewerage effluent
  • Industrial waste water treatment systems
  • Hydroponics
  • Almost any application where you need to measure the oxygen content of a liquid
  • Air quality monitoring, environmental warehouses

Technical Properties

New Oxygen Probe

The oxygen probe is a galvanic cell, basically the probe acts like a battery in which there are two dissimilar metals in a conducting electrolyte solution. The anode is zinc and the cathode is silver, oxidation takes place on the surface of the anode to form a white deposit of zinc oxide. The rate of oxidation is a function of the diffusion of oxygen through a semi permeable Teflon membrane, which is in turn directly related to the partial pressure of oxygen in solution, or in the air. A potential difference is established in the probe, the milli volt out-put being approx. 8mv per 1 mg/l of dissolved oxygen. This gives the probe a reading of approximately 80mv when in air. Any length of good quality two core (0.5mm squ, multi-strand) cable can be connected to the probe, technically there is no limit to the length of cable that you can attached, however we have only tested to 2000 meters. General maintenance is also very easy, all that you need to do is keep the probe membrane reasonably clean, this is achieved by giving the membrane a wipe with a cloth once a week.


There are two types of membrane available for our Oxygen probe. The standard is a Teflon membrane which is temperature compensated in the probe to give very accurate measurements of oxygen in ppm or mg/l. The second type of membrane is made from Polythene and is designed for use with our probe when measuring oxygen in percentage saturation % sat.

The Teflon membrane is slightly better than the polythene membrane and mg/l oxygen measurement are more meaningful than % saturation membranes so we always include Teflon membranes as standard unless requested to provide polythene membranes for % saturation. If you only plan to use % saturation as a measurement then only order the polythene membranes. Teflon membranes sink and %sat polythene membranes float.