PH Probe Calibration

[dwsindy]

When calibrating PH probe how long does it take to settle or stop changing? Should this take several minutes?

[kenargo]

About 5 minutes, if it's more than 7-10 minutes that could be an indication that the probe is getting old and needs replaced. Probes, when they get old, get slow.

[dwsindy]

Thanks,
It does seem to take longer than five minutes but age shouldn't be a factor. the probe is only a few months old. I calibrated the probe today and then calibrated my digital pocket ph meter and after calibrating the two measurements of tank water are different and when I check again with the calibration fluid the pocket meter is dead on but the probe is off .2. Could I have a bad probe?

[kenargo]

It should read dead on once calibrated; try recalibrating and leave longer but you could have a probe that is going bad.

[sleeperls]

Make sure your calibration fluid is good. Plus the tip of the probe is nice and clean. I did mine again last night for the 2nd time with new fluid since i thaught mine was off. My test kits always showed my ph was higher than the probe was reading.

I tried it with the old fluid again and it was still off. I did it again with new hanna fluid and it is now right on.


I had reading of 7.7-7.8, now it reads 8.0-8.1 just as my test kits do.

With the new fluid it settled in less than 5 min. The old fluid took forever.