I have a pH monitor on my tank for a few months, calibrated it per instructions and the numbers it detected looked "reasonable" to me and I had no reason to doubt it...until one day. It always read 8.1-8.4 on my tank until one day the reading just plummeted from 8.4 to 7.4 instantly and Ive been struggling to bring it back up to 8.4 since. I tried measuring various other things to make sure my prob is reading "correctly". Im dosing kalk so I dunked the probe in kalk water and it reads 12+ pH. Dunked it in citric acid solution and it reads around 4ish pH. My tank still reads 7.8-8pH at best.
This morning I woke up to my tank having only 6.6pH. I moved the probe else where in my sump, fully submerged the prob so its picking up the reading from the bottom of my sump and its reading 2.13ph???????? I lifted the probe back up near the surface and its reading 6.8ph. Theres no way in a sump with fast moving flowing through it that the bottom has a pH reading of 2. This leads me to think my pH probe is bad? Ill try and calibrate the probe again tonight to see if this makes any difference, but most likely I have to get a different unit.
This morning I woke up to my tank having only 6.6pH. I moved the probe else where in my sump, fully submerged the prob so its picking up the reading from the bottom of my sump and its reading 2.13ph???????? I lifted the probe back up near the surface and its reading 6.8ph. Theres no way in a sump with fast moving flowing through it that the bottom has a pH reading of 2. This leads me to think my pH probe is bad? Ill try and calibrate the probe again tonight to see if this makes any difference, but most likely I have to get a different unit.