Resolving pool pH probe issues: Effective interaction between customer and technical advisor.

Client:
I have sent you an email with my questions...

Technical Advisor:
Hello, When?

Client:
Hello 🙂 Here is what I wrote:
I bought a PH probe to install on a Hayward Aquarite Pro device.
The pool water is tested at 7.6 and even higher with reagent drops.
The aquarite indicated 7.3. I recalibrated the probe to 7.0 with a calibration solution and reinstalled the probe. The aquarite now indicates 7.0 and doesn't change much, despite the water's apparently high PH.
So I have doubts about the proper functioning of the probe. How can I test if it is working correctly?
A lifespan of 1 year seems very short if it is defective.
The PH probe was purchased a year ago.

Technical Advisor:
Do this little test, that way we will know if it's the probe https://ph-redox-pool.com/gb/content/16-ma-sonde-ph-est-elle-hors-service-

Client:
Great, thank you very much. I will do the test tomorrow. Do I need to use a lot of vinegar?

Technical Advisor:
No, just a tablespoon.

Client:
Okay, perfect. Thank you for your quick response. I will come back to you if needed.
Have a great evening.

Technical Advisor:
You're welcome, don't hesitate to contact us again! Have a good evening.