Ph Probe issues

[Bob Escher]

i have. the Apex Classic had it now for allmost two years.
Have calibrated my Ph probe four times.
I'm going to presume the first couple times I did it wrong and it read in the low 7.20 ( when I had fresh water
When I went to Salt 16 months ago I calibrated it again and it read low two weeks ago I calibrated it and it was fine at first but then it dropped to days later to 2.76 and stayed there
Yesterday as I watched the BRS video on calibrating it I calibrated it.
I then tested it in the 7.01 calibration fluid ( the last cal was in 10) and it went down to 7 and was fine
I then but it into my sump where it started climbing I did this at 1:00pm by 9:00 pm it had climbed to 9.04 this morning at 5:00Am it is down to 7.61
I am going to presume that the prove is bad?
Thanks

 

[Brew12]

i have. the Apex Classic had it now for allmost two years.
Have calibrated my Ph probe four times.
I'm going to presume the first couple times I did it wrong and it read in the low 7.20 ( when I had fresh water
When I went to Salt 16 months ago I calibrated it again and it read low two weeks ago I calibrated it and it was fine at first but then it dropped to days later to 2.76 and stayed there
Yesterday as I watched the BRS video on calibrating it I calibrated it.
I then tested it in the 7.01 calibration fluid ( the last cal was in 10) and it went down to 7 and was fine
I then but it into my sump where it started climbing I did this at 1:00pm by 9:00 pm it had climbed to 9.04 this morning at 5:00Am it is down to 7.61
I am going to presume that the prove is bad?
Thanks

Sounds like the probe could be bad. Have you tried cleaning it? If you think the probe is failing you can try soaking it in a 50/50 vinegar and DI water solution for 6 hours then clean it with a soft brush. This might get it working again.

 

[Bob Escher]

Sounds like the probe could be bad. Have you tried cleaning it? If you think the probe is failing you can try soaking it in a 50/50 vinegar and DI water solution for 6 hours then clean it with a soft brush. This might get it working again.

I will try that thanks

 

[Bob Escher]

Well I soaked it for more than six hours plugged them back in recalibrate tested it on both fluid after I calibrated and it showed the correct reading but it back into the sump and the reading are all over the place yesterday was in 9.5 range this morning 6.7

The other thing I can't figure out is when I had it disconnected apex still showed a reading how can that be
Thank

 

[Brew12]

Well I soaked it for more than six hours plugged them back in recalibrate tested it on both fluid after I calibrated and it showed the correct reading but it back into the sump and the reading are all over the place yesterday was in 9.5 range this morning 6.7

The other thing I can't figure out is when I had it disconnected apex still showed a reading how can that be
Thank

I've noticed the Apex will lock in values when things get disconnected sometimes. It does make it confusing.

Do you run with a ground probe in your system?

If you take the probe out of the sump and dip it back into the calibration fluids, is the reading close to accurate?

 

[Bob Escher]

I've noticed the Apex will lock in values when things get disconnected sometimes. It does make it confusing.

Do you run with a ground probe in your system?

If you take the probe out of the sump and dip it back into the calibration fluids, is the reading close to accurate?

Yes I do have a grounding probe in the sump as well
and yes I did recalibrate it and did test it with the cal fluids before I put it back in.
Are you suggesting to take the grounding probe out and see what happens

 

[Brew12]

Yes I do have a grounding probe in the sump as well
and yes I did recalibrate it and did test it with the cal fluids before I put it back in.
Are you suggesting to take the grounding probe out and see what happens

I was wondering if you could have had a voltage issue in your tank that could be causing the pH reading issues. If you use a grounding probe that is very unlikely.

I wasn't clear enough on the calibration. After the cleaning how far off was it when you put it in the calibration fluid, but prior to calibrating it? For instance, if you would take the probe out of your system right now and put it in a fluid with a pH of 7, what would it read?

 

[Bob Escher]

I took the probe out and placed it 7 with a reading of 5.79 both with temp comp on and off
put it in ten and got 8.79 with temp on and off
put it back into the tank and have a reading of 6.69 or 6.75 or 6.95 yes its jumping around

 

[Brew12]

I took the probe out and placed it 7 with a reading of 5.79 both with temp comp on and off
put it in ten and got 8.79 with temp on and off
put it back into the tank and have a reading of 6.69 or 6.75 or 6.95 yes its jumping around

Sounds like it is time for a new probe.

 

[Bob Escher]

Yep thanks

But the strange thing is it's settle down now at a nice 6.77 and it's staying there

 

[Grey Guy]

It is my understanding that the Apex standard PH probe may only be good for about a year. I bought the new double lab grade probe a few months ago and it is reading about .4 low after calabration. According to my probe, my PH never gets above 8. But if you add .4 to 7.8, you get 8.2. 8.2 or greater is what my test kit reads. Here is where I need some help. If I am calibrating with 7.0 solutions, shouldn't the reading be 700. But is it's higher or lower then it skews the PH reading. What I observe is that if calibration reads 740 and 1040, then it compensated by lowering the reading to 700 and 1000. By doing this though, it causes the probe to be off -.4. Like I said, when I add .4 to my reading, then it matches my test kit pretty close.