Calibrating PH probe for Apex

[InvaderJim]

That's some good growth

 

[nothing_fancy]

Silly question but are you rinsing the probe in RO between the two calibration solutions you're using? I didn't do that during my first Cal of a probe and it definitely through off the readings.

 

[Tuan’s Reef]

yes, rinse the probe in RO water. I then dry it off before setting it in a new solution.

 

[Dburr1014]

yes, rinse the probe in RO water. I then dry it off before setting it in a new solution.

I bought some fresh packets of 7 and 10 and recalibrate this morning. Failed the 1st time around.
Did it again and 7 was 734 and 10 was 1056.
Before my pH was reading 7.8/8.0 night/day. Now it's 7.69
This apex manual calibration a absolutely sucks. I have 0 confidence that it's right. Everytime I calibrate it reads lower.
I'm going to check when I get home after work but I'm sure it's not right.