PH question

[Steven91]

I'm not trying to chase per say but I do have a question.

My Apex controller pH is registering my pH at a really low 7.35 (did a water change a few days ago about 10% volume) though when I test with my api test kit im getting 8.4...what gives?

I did calibrate the probe when I got it and it's only maybe 3/4 months old...do they really lose calibration that quick or do I have another issue?

 

[clsanchez77]

I'm not trying to chase per say but I do have a question.

My Apex controller pH is registering my pH at a really low 7.35 (did a water change a few days ago about 10% volume) though when I test with my api test kit im getting 8.4...what gives?

I did calibrate the probe when I got it and it's only maybe 3/4 months old...do they really lose calibration that quick or do I have another issue?

I would verify that calibration but checking it against the calibration solution in regular mode. Did you notice if the pH probe drifted over time, of just suddenly started reading low? If it drifted, it could be the probe and/or calibration. If it was a sudden change, you likely have electrical interference. Check the probe wire routing to make sure its not tangled or coiled with other wires or parallel to electrical wires. Could also be stray voltage, which you can verify with a volt meter and/or eliminate with a ground probe. Ultimately, you will want to identify that source and eliminate it, aka replace the faulty equipment.

 

[Steven91]

I would verify that calibration but checking it against the calibration solution in regular mode. Did you notice if the pH probe drifted over time, of just suddenly started reading low? If it drifted, it could be the probe and/or calibration. If it was a sudden change, you likely have electrical interference. Check the probe wire routing to make sure its not tangled or coiled with other wires or parallel to electrical wires. Could also be stray voltage, which you can verify with a volt meter and/or eliminate with a ground probe. Ultimately, you will want to identify that source and eliminate it, aka replace the faulty equipment.

I'm gonna get some calibration fluid in the next few days as well as have another test kit test my water (more points, should help narrow it down a little), I have my pH and temp probe in the Apex holder in my sump in the return pump area. And for the most part my pH has been steady between 7.8 and 8.2 over the last few weeks.

 

[Randy Holmes-Farley]

Almost certainly pH 7.35 is wrong. if real, if is definitely worth raising.

 

[Shaun Sweeney]

If the probe wiring runs 6" or more in close proximity to a 110 volt wire, the a/c will induce current into the probe wire - shielded or not.

 

[Steven91]

So, looks like my PH is finally heading back into normal ranges, moved some cabling around (thank you velcro ties) to make sure i dont get any interference from a/c