Help! Problem with pH probe on apex

ReefAddiction34 · Oct 28, 2018

So I tried being a responsible reefer today and decided to clean and recalibrate my pH probe. Well afterwards the reading is now significantly off. My pH is usually 7.9-8.1, my pH probe is now reading 7.47.
It’s strange because when I have the probe in the different calibrating solutions... the reading is accurate (7 and 10), but in the tank the reading is 7.47???? Anyone have ideas about what’s going on?
I have an apex jr and PM1. They are both updated and have been working fine before today, after I cleaned and tried recalibration. I’m getting pretty dang frustrated that this simple process has turned into an epic head ache.
I have tried recalibrating both on the display as well as apex local... neither is working. I have unplugged the pH probe and restarted the apex several times and nothing! I know that my tank is not at a pH of 7.47, so something is very off. Please let me know if you have any ideas.

SecondCityCorals · Oct 28, 2018

The PH probe on my Apex is also terribly off. When I calibrate it, it seems fine for awhile. But within a week or two drifts by 0.3 or more. This is very worrisome and not acceptable if you ask me. I'm about to get a calcium reactor which will be controlled via PH. So if my PH is off, then I could end up running my calc reactor wrong and nuke my entire tank.

Overall, I am displeased with Apex. I have other issues where the base unit requires being reset once per day, otherwise it just magically drops offline.

ReefAddiction34 · Oct 28, 2018

Yea I agree, apex can be very frustrating at times and unnecessarily complexed if you ask me. The first time I set up the pH probe I had this issue and had to mess around with it, constantly resetting and it worked but I don’t even know what I did to make it work... and now again I’m in the same boat, pH probe is reading 7.3 this morning in my tank.... which is completely wrong. It’s just frustrating.
If anyone has had success using a different method for calibration or if they know of an additional step I’m missing please inform me! Otherwise I guess I just have to contact apex to see if they can help via email or just call them on Monday.

n2585722 · Oct 28, 2018

How old is your probe? What does it read if you place the probe in a cup or glass of tank water? The cup or glass will isolate the probe from the tank itself as a test to see if there is some kind of stray voltage that is causing a error in the reading.

Aquavaj · Oct 30, 2018

Mine started acting weird too after I cleaned and calibrated it to be moved to a new tank. It's reading .3-.4 off. I've seen it hit 8.7 which is almost impossible. Haven't bothered to recalibrate it yet.

ReefAddiction34 · Nov 8, 2018

n2585722 said:
How old is your probe? What does it read if you place the probe in a cup or glass of tank water? The cup or glass will isolate the probe from the tank itself as a test to see if there is some kind of stray voltage that is causing a error in the reading.

No stray voltage or EMI. Checked for both. I tried a new probe based on Neptune’s advice and this didn’t fix the issue either. So I’m probably going to send in the PM1 module to see if it’s a bad port. Just ticks me off that everything was working flawlessly, and then this happens after cleaning and calibrating???? Sounds fishy... no pun intended. It seems a lot of people are having issues with apex and proper pH readings... that just blows my mind given the cost of their units. It should be easy to use, reliable and accurate period.

Isaac Alves · Jul 3, 2019

I know this is an old thread. I hope everyone is still reefing happily and with at least some success. I've never cleaned my ph probe. Does anyone know what to use to clean an APEX ph, orp, salinity probes? I've sure I've got build up and stuff. My salinity is definitely shot. Can I just soak them in HCL? then gently brush them clean and rinse with RO water? Then re calibrate?

Thank you,
Isaac