Hi

I have now two ph probes, the news one is well calibrated since i checked it in solution and it gives the good value. I put it in the cell along with redox-temp-cond probes. It gives me a ph around 7.8-7.9 witch is a little bit low. My other probe, older that is sitting in an other tank same system gives me ph 8.00-8.10... This one is also calibrated and gives the good value since i also double checked. What could cause the difference? Interference? other probes near by??