Ken Anderson wrote:
"gene" wrote in message
.. .

Ken Anderson wrote:

When using a pH meter, do you stir the probe in your liquid, or do you

hold it

still? Dumb question, but thanks.
Ken



Being the delicate probe a pH probe is, I prefer not to stir with it.
I just swish my liquid in my beaker and gently lower the probe into it.

Regards,
Gene



Thank you Gene. I am trying to figure out why I got 3 different readings in a
row. Tomato sauce, actually. I calibrated, tested. Recalibrated, tested.
Recalibrated, tested. Even if my pH 4 and pH 7 fluids were old, I'd expect
repeatability. Two place resolution, +/- .04 accuracy. I got 4.41, 4.16, and
4.30.
Ken


Hmmm.... could the solids in the tomato sauce have gummed up the pH
sensor electrode so that it is not being flushed adequately between
readings? I wouldn't expect recalibration to get you back to the
start if there's a barrier to solution transport across a tomato solids
layer.
You have an interesting dilemma. Any gurus out there to help?
Gene