In order to perform ORP (Redox) measurements, a Redox electrode must be used in combination with a reference electrode. We offer both integrated and external soil reference electrodes for ORP measurements. See REF-12-0-A – SWAP instruments for additional information.

Our reference electrode is a double junction 3 M KCl gel Ag|AgCl reference electrode. Reference electrodes do need maintenance. For our reference electrodes this means refilling with 3 M KCl gel.

The maintenance frequency depends, amongst others, on soil type, soil moisture content and (ground)water table fluctuations. We have reduced the maintenance frequency of our soil Redox probe by applying a microporous polyethylene (MPPE) ring in our reference electrode. This is the white ring on the photo.

The MPPE ring offers very good contact between the reference electrode and the surrounding soil or sediment, with a minimal leakage of electrolyte. This results in very stable measurements. Depending on local conditions, maintenance frequency now varies between quaterly to yearly.  The MPPE rings can also be used in the older models of our soil reference electrodes. Soon, the rings will also be available separately (bag with 5 pieces).

Feel free to contact us at info@swapinstruments.com for questions about our products and applications.