Calibrating ORP Probes

In order to ensure the ORP value of your pool is accurate, calibration of the probe is essential.

Calibrating the ORP probe ensures the electrode inside of it has not drifted off or is damaged. Inaccurate ORP readings can result from poor calibration, storage, and after the cleaning of a dirty probe.

We recommend calibrating/recalibrating your ORP probe when:

  • The ORP probe is new
  • The ORP probe has not been used for a while (ex. in the spring, if your pool was winterized)
  • You have recently cleaned the ORP probe
  • If the results from manually testing the water differ significantly from the reading of the probe
  • Annually as a maintenance item

You will need to have some ORP-225 calibration/storage solution available to place the probe into. You can find this product at many online storefronts, or possibly from local retailers.

Steps to Calibrate the ORP Probe

The steps to calibrate are pretty straightforward – using Installer Mode, select the ORP probe you will be calibrating. Press the blue “Calibrate” button to begin.

Before calibrating the ORP probe, ensure that the ORP solution you are using is within date, and is fresh!

Press the blue button next to Status and turn it ON.

You will see the current reading from the probe and an option to calibrate to the base reading of 225.

Calibrate the Reading to 225

  • Rinse the ORP probe well with demineralized, deionized (DO), or reverse osmosis (RO) water.
  • Open the ORP calibration/storage solution and optionally pour some fluid into a separate, clean container small enough to submerge the tip of the ORP probe into.
  • Place the ORP probe into the solution, and let it sit until the readings stabilize (this usually takes 1-2 minutes but could take longer)
  • Once the readings have stabilized, press the Calibrate button. This will set the new calibration at 225.

Used calibration fluids are not considered accurate after 20 minutes. Do not reuse and dispose of them properly.

When an ORP probe reaches the point where it no longer provides accurate readings or is unable to stabilize in the buffer solutions, it is time for a replacement pH probe.

Updated on July 21, 2023

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