Help PH Probe Broken Or High PH?

AviR · Apr 24, 2026

Not sure what’s going on in my tank everything looks great but my apex keeps giving me high ratings on my PH probe, I just cleaned it and I recalibrated and it only went higher. During cleaning I thought I might’ve snapped off a little gold rod that comes out of the Apex Probe but it was reading high even before it broke (and not sure if that wasn’t just a clump of dirt as I couldn’t find it). I’ve been getting a reading of 8.5 during daytime for the last month or two and now it’s gone to 8.6 and
above. Alk did rise a month ago to 13 dKH from 12 but everything stayed healthy. I’ve now slowly lowered down to 11.96 and will continue dropping it to 10 or 11. Still the ph keeps rising. The tank has good gas exchange and surface movement.

Will try to find an LFS that has more calibration solution because I just discovered I let my Hanna to dry out.

Any suggestions @Randy Holmes-Farley?

mcarroll · Apr 27, 2026

You can make some DIY calibration solution from Randy's recipe.

You can run Randy's aeration test to see if your results change post-aeration.

Randy Holmes-Farley · Apr 27, 2026

Be sure to take the probe after calibration (or now) and retest in the calibration fluids.

pH could be that high, and also is not a problem, but typically tanks have enough aeration to drive it lower unless you are using hydroxide in some form for alk.