I have a problem ! my device apparently works, however reading the

I have a problem ! my device apparently works, however the PH level reading seems to appear much lower than the actual PH reading taken with strips. I have however adjusted the value to PH 7.00 with a buffer solution.

Hello, try to test your probe like this https://ph-redox-pool.com/gb/content/16-ma-sonde-ph-est-elle-hors-service-

OK Thank you but indeed my probe is not very young.