Measurement Gap on Test Strip and Astral Pool: How to Test Your Probe?

Client:
Hello, I have two different measurements on the test strip, one is at 6.9 and the other one on the astral pool is at 9.0. Thank you for your response.

Technical Advisor:
Hello, first you need to test your probe. See here.

Client:
I think it has a defect.

Technical Advisor:
It looks like it, do the test, it's quick.

Client:
It's one year old.

Technical Advisor:
It can happen!

Client:
The link is in English.

Technical Advisor:
Sorry, one moment. See here.