When using a pH meter, do you stir the probe in your liquid, or do you hold it
still? Dumb question, but thanks.
Ken

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

"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

"Ken Anderson" > wrote in message
...
> 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.

Personally, I'm from the "stir gently, wait, stir again and wait until the
reading stabilizes" school. I do this when running standards too. It takes
time for the reading to settle to a final value. Also, the time required to
stabilize will lengthen with age of the probe. Supposedly, contact lens
enzyme cleaner helps restore/clean dirty probes.

BTW, I had trouble with flaky connections between the probe and body of my
Hanna Piccolo, so I soldered jumper wires between the sets of contacts.
That did the trick.

Tom S

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

Do you use probe cleaning fluid to clean the probe once in a while. I find
that that will help consistence.

Ray
"gene" > wrote in message
m...
> 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

"Ray Calvert" > wrote in message
...
> Do you use probe cleaning fluid to clean the probe once in a while. I find
> that that will help consistence.
>
>
I have only used it once, which was last season. I stored the probe in the
little tip it came in, submersed in whatever solution that is (KNO3?). The
instructions say to soak it in 7 pH calibration fluid for several minutes to
freshen it up. I didn't do that but will next time. I did use distilled
water for my probe rinsing. In truth, I must admit that the calibration
solutions I used this year, were left over from LAST year, stored in little
Mason jars. I have "fresh" packets of 4.0 and 7.0 from last year. I'll at
least break those out and try again.
Ken

"Ken Anderson" > wrote in message
...
> 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.

Personally, I'm from the "stir gently, wait, stir again and wait until the
reading stabilizes" school. I do this when running standards too. It takes
time for the reading to settle to a final value. Also, the time required to
stabilize will lengthen with age of the probe. Supposedly, contact lens
enzyme cleaner helps restore/clean dirty probes.

BTW, I had trouble with flaky connections between the probe and body of my
Hanna Piccolo, so I soldered jumper wires between the sets of contacts.
That did the trick.

Tom S

"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

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