ph probes, test kits, oh my!!!!
 

So I am pulling my hair out

my new apex ph probe is reading 7.91

while my seneye is reading 8.12

hagen ph hest kit 8.3
api test kit reads 8.2


I have calibrated the apex with pinpoint 10, 7 calibration fluid,, twice ...

any suggestions ?

i wouldn't be overly concerned.

most people don't check their PH at all if they don't have a probe.
your in the ballpark so dont worry

yep that's the message I'm getting..
 

but when you spend over 1k on apex gear,, you'd expect it to match up with at least 1 out 3 other ph tests..

True

First suggestion: Throw out the Hagen and API kits and remove them from the equation. A pH test kit is fairly useless if you want to get within 2 points. Considering you calibrated the Apex probe, I'd be inclined to believe that the most. I'm not sure how Seneye usually compares.

I agree with e46er, you're within range, so I wouldn't be too concerned.

I agree with the other replies
Have you checked the apex and seneye in new 7 and 10 fluids, after calibration?
Also, stray current and electrical fields can skew pH probe readings. Try putting some tank water in a glass and test that with the probes, but 1 at a time.

Good advice. :thumb: