pH tester does not match drop test

brimorga · Nov 22, 2021

Moved from here.

skyeboysteve said:
I have a digital pH tester that goes up to 14. I calibrate it routinely so that it's accurate to 0.01 on the scale.

sorry for highjacking, but I calibrated my pH meter and I think I screwed it up cause it always reads higher than the TF pro. How are you doing regular calibration? Do you have a stock of the test powders that came with it, or are you doing it another way? I also am fighting high pH and using lots of acid, but I have new plaster so I guess that is to be expected.

ajw22 · Nov 22, 2021

How much of a discrepancy do you have between the pH meter and the drop test?

What pH meter do you have?

What calibrating solutions do you use?

Constantly rising pH is normal for new plaster.

What is your TA?

brimorga · Nov 22, 2021

ajw22 said:
What pH meter do you have?

What calibrating solutions do you use?

Constantly rising pH is normal for new plaster.

What is your TA?

How much of a discrepancy do you have between the pH meter and the drop test? About .5 higher on the pH meter.

What pH meter do you have? I have the one that came bundled as an add on with the TF-Pro salt kit, just got it about a month ago. The PH-009 (I)A

What calibrating solutions do you use? I only had the 2 packets that came with the original kit, thought I got it spot on for what it should have said, but I guess not! I will admit, I did have a heck of a time getting the screw to turn and getting it calibrated, was a very frustrating experience. Not sure if there is anyway I can calibrate it again besides for just getting it to match the TF-100. That might be sufficient.

What is your TA? 80

ajw22 · Nov 22, 2021

This one?

I have tried using that meter and it is low end and loses calibration too easily. Calibration seems to drift as the battery declines.

Look at the Apera PH20 meter.

And look at using pH 7 calibrating solution.

wireform · Nov 22, 2021

Same here, had that one and was always unreliable. I like the regular Taylor PH test kit, it takes a whole 2 seconds to get a perfect reading.

HermanTX · Nov 22, 2021

brimorga said:
What pH meter do you have? I have the one that came bundled as an add on with the TF-Pro salt kit, just got it about a month ago. The PH-009 (I)A

I had the same issue with this pH meter. I was constantly calibrating it and finally stopped using it. I put the following on my Christmas wish list.

Apera Instruments AI311 Premium Series PH60 Waterproof pH Pocket Tester Kit, Replaceable Probe, ±0.01 pH Accuracy: Amazon.com: Industrial & Scientific

smile.amazon.com

brimorga · Nov 22, 2021

ajw22 said:
This one?

I have tried using that meter and it is low end and loses calibration too easily. Calibration seems to drift as the battery declines.

Look at the Apera PH20 meter.

And look at using pH 7 calibrating solution.

Thanks Allen! It's very similar to that one, the only thing I noticed is mine only goes to .1 not .01 (not that I need .01). Makes sense about it being low end, I'll look for the other solutions you recommended.

brimorga · Nov 22, 2021

HermanTX said:
I had the same issue with this pH meter. I was constantly calibrating it and finally stopped using it. I put the following on my Christmas wish list.

Apera Instruments AI311 Premium Series PH60 Waterproof pH Pocket Tester Kit, Replaceable Probe, ±0.01 pH Accuracy: Amazon.com: Industrial & Scientific

Apera Instruments AI311 Premium Series PH60 Waterproof pH Pocket Tester Kit, Replaceable Probe, ±0.01 pH Accuracy: Amazon.com: Industrial & Scientific

smile.amazon.com

Thanks! I added that one to my cart as well as the PH20, we'll see if Black Friday brings a deal. Good to know that the PH tester I have is not worth my time, it drove me crazy just to get it initially calibrated.