pH Meter Calibration

[myndflyte]

I recently bought the Thermoworks 8689 pH meter along with the calibration solutions. Out of the box, I tried calibrating at 7, then 4, and then 10. Once I did the pH 10 calibration, I get an error that the slope is out of whack. In talking with Thermoworks customer service, they sent me some electrode cleaner, which of course got lost with USPS. In addition, customer support has stopped responding to me lately as well.

So, my question is, if the calibration of pH 7 and pH 4 didn't cause any errors, is there any reason to do the pH 10 calibration since all my readings will be in the pH 4 range anyway?

 

[WesBrew]

My meter came with the 4 and 7. so I do a 2 pt. calibration. I don't think a third is needed. maybe your meter doesn't recognize the third during calibration mode.

 

[myndflyte]

My meter came with the 4 and 7. so I do a 2 pt. calibration. I don't think a third is needed. maybe your meter doesn't recognize the third during calibration mode.

It recognizes it as it will automatically register that it is a pH 10 calibration solution. I finally heard back from customer service and they said a 3 point is more accurate but 2 point would suffice.

 

[bracconiere]

i've read that you only do a 2 point in the direction your testing for, so if your testing acid's do a 7 and 4, if your testing bases do a 7 and 10....And in my experience Auto calibrating ph meters suck the big one...I got a milwaukee manual config, works great.. MW-101, been working great for years, same probe even. and my MW-101 only has 2 points, a 4/10 and a 7....so i think that's actually the way it works...

 

[mabrungard]

If you'll be assessing pH across a broad range, then the 4,7, 10 calibration may be needed. But for brewing use, just the 4,7 calibration is sufficient.