PH probe gone Bad???

[Nick Rose]

I think my PH probe has gone bad. It’s the original probe that came with the Reedkeeper Elite. I recalibrated it two times. The probe is indicating that the PH is 7.54 at 3pm PST. But it just doesn’t make any since. Yesterday it was showing above 7.8. Also it seems like the PH goes down during the day and up during the night. I’ve checked the other parameters and nothing is off. I checked with a API High Range PH test kit and it shows 7.8. I then checked water from the downstairs tank with the probe and it shows 7.76 and the API shows 8.0. Before I put out $60 for a new probe does everyone agree that it has gone bad?

 

[Dr. Dendrostein]

I think my PH probe has gone bad. It’s the original probe that came with the Reedkeeper Elite. I recalibrated it two times. The probe is indicating that the PH is 7.54 at 3pm PST. But it just doesn’t make any since. Yesterday it was showing above 7.8. Also it seems like the PH goes down during the day and up during the night. I’ve checked the other parameters and nothing is off. I checked with a API High Range PH test kit and it shows 7.8. I then checked water from the downstairs tank with the probe and it shows 7.76 and the API shows 8.0. Before I put out $60 for a new probe does everyone agree that it has gone bad?

Once I had a bad pH probe and it wiped out my corals bummer spend a little money and hopefully you'll have peace of mind

 

[redfishbluefish]

Likely it's bad, but I'd give it one more chance by cleaning. Soak it in vinegar for a day and then rinse and recalibrate, and see if that helps.

 

[lolgranny]

Likely it's bad, but I'd give it one more chance by cleaning. Soak it in vinegar for a day and then rinse and recalibrate, and see if that helps.

This. Clean, re calibrate. Or bust out bust out $60? Or don’t have one. Ph smeeeeee H. +15 years and no ph meter

 

[Randy Holmes-Farley Verified Community Expert]

Controllers often don't do a good job on pH. Note sure if that relates to temperature corrections, ground loop problems, electrical interference, or something else.

Does the controller properly measure the calibration solutions at tank temp immediately AFTER completing the calibration?

 

[Nick Rose]

Yes it does. Once I finished the first calibration I checked and it measured properly. Before I calibrated the second time i checked and it was off. Once that calibration was done I checked and it read properly. I’m heading off to the fish store to get calibration fluid to check one more time before buying a new probe.

 

[Randy Holmes-Farley Verified Community Expert]

Usually, if a probe can read calibration solutions correctly, it's hard to imagine exactly how it would be off for a pH value in between those calibration points (but other factors like a ground loop in the tank could be). I know that once Craig Bingman claimed it could, but I'm not sure how that would be, at least to an extent to be off by more than 0.1 pH units or so.

 

[Nick Rose]

Just took it out of the vinegar bath and rinsed it with RODI water. Like the other calibrations it takes a half hour for it to bottom out and just bounce around a few numbers. I checked the calibration and it was off. 9.97, 7.00 and the temperature of the calibration fluid is 74 F