PH 51 Question

weaselbaw

Member
Hello,

Hopefully someone can answer this for me.

I have a PH 51 that reliably measures the PH of a small sample (1-2 cups) taken from the res at about .5 higher than if the probe is placed directly into the res.

Maybe someone can explain this to me.

Thanks!
 

tea tree

Well-Known Member
by .5 yu mean it really hits 6 instead of 5.8? I would think that is odd. Maybe a lot of factors. i use a ph 53 I think it is. MAybe 56. clean the cup out and try reading the samples and reservoir with all diferent variables in check. Mine has no issues. Maybe recalibrate. Check batteries. Weird. They temp compensate. Try again. It is electronic and weird shot happens. I love my milawaukee too.
 

weaselbaw

Member
by .5 yu mean it really hits 6 instead of 5.8? I would think that is odd. Maybe a lot of factors. i use a ph 53 I think it is. MAybe 56. clean the cup out and try reading the samples and reservoir with all diferent variables in check. Mine has no issues. Maybe recalibrate. Check batteries. Weird. They temp compensate. Try again. It is electronic and weird shot happens. I love my milawaukee too.
By .5, I mean that if it reads 5.5 in the res, it reads 6.0 in the sample. I considered temp change as the culprit, but the change happens instantly and is unaffected by sitting. Water changes temp over time. Therefore, it can't be the temp. I considered interference from the magnetic recirc pump, but no joy there either. Did a recalibration and that wasn't it either. Now I'm off to change the batteries.
 

weaselbaw

Member
Ok. I got a brand new PH 51 and I am still having exactly the same issue. Is it possible that the amount of water affects potiential hydrogen?

When I have the probe in the res and its reading low the reading immediately rises to equal the reading of the sample as soon as the probe is removed from the res (but is still wet). I've noticed that when calibrating (or resting in storage solution), the reading does not change when the probe is removed from the solution until the liquid is shaken off the probe. This leads me to believe that the reading in the sample is the accurate reading. Am I missing something here?

I would appreciate it if some of you would duplicate my method and report you findings. Does your sample have the same reading as a direct reading from your res?

Thanks
 

tea tree

Well-Known Member
ok. I just tried to measure the res and a cup of res water. They both read the same. At first as usual I had to swish the probe aroun d a little and wait a few moments. That prob cant be your prob.

I have a ph 55.
 
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