The
probe is reading 7.7 while the test kit shows 8.2. Odd they would both show
a much closer,but higher reading in the tank water.

I might be mistaken, but I think pH probe's work on some sort of exponential
curve. That's the reason for two point calibration, you check two places on
that curve to make it isnt bending faster or slower. Somewhere online there's
a diagram or table that plots what inaccuracies you would have if you used 4.0
and 7.0 to calibrate a probe that was measuring a 7.0+ solution versus using
the correct 7.0 and 10.0 calibration. I can't remember, but I think it was
somewhere in between 5-10% it could be off by.
~John