Troubleshooting Unstable Readings in pH and Redox Probes: A Customer-Advisor Dialogue

Client:
Hello,

Technical Advisor:
Hello

Can I help you?

Client:
Last year, I bought pH and redox probes from you, thinking that I was purchasing quality equipment compared to other suppliers... Unfortunately, the redox probe is not working despite being properly winterized in a solution protected from freezing... When I put it back into service, the measurement quickly oscillates between 400 and 600... Calibration is fine with a fixed value. TAC is okay 😕

pH is 7.2

Technical Advisor:
How long ago did you restart the system?

Client:
It's been 1 month since I restarted it.

Technical Advisor:
Have you recently done any treatment?

Client:
At the end of April... So it's been 2 months.

Technical Advisor:
Did the problem start immediately when you restarted it or did it start suddenly?

Client:
When I do a shock chlorination, I turn off the regularizations.

Since the restart, despite several calibrations,

I have never had a "fixed" value.

Except in the calibration solution. So I checked the TAC, which is okay.

Technical Advisor:
The value is unstable then, if you put it in the calibration solution, is the reading stable at the calibration value? Is that value stable?

Client:
Yes, that's right. It's strange 🤔