Ph Calibration

[mginster]

I went to calibrate my probe today. Rinsed in RODI, dried a little with a paper towel, dipped in 7.01 (read 7.43) dipped in 10.01 and read 10.02.

After saving it now thinks my tank is at 8.01 when it was at 8.28 immediately before. That seems like a fairly large drift to me.

Was my 7.01 solution off? It seems odd it would be almost half a point different.

For cleaning probes is there any standard? I see a lot of people mention vinegar, some citric acid, some never. Some say use a brush, some say don’t.

I am ordering new calibration fluids to test again.

 

[Randy Holmes-Farley Verified Community Expert]

The recalibration was a significant change. Unless there’s a reason to doubt it, the new calibration is must likely correct, but getting new pH 7 and 10 fluids would be a good test.

How to clean a pH probe depends on what is on it. Acids remove calcium carbonate, while very gentle brushing can remove algae. Mine were in the dark and I only used acid.

 

[ChrisfromBrick]

The recalibration was a significant change. Unless there’s a reason to doubt it, the new calibration is must likely correct, but getting new pH 7 and 10 fluids would be a good test.

How to clean a pH probe depends on what is on it. Acids remove calcium carbonate, while very gentle brushing can remove algae. Mine were in the dark and I only used acid.

@Randy Holmes-Farley, would a mild citric acid solution for 15-20 min be ok for cleaning calcium deposits (or other things) on it? After that- I want to recalibrate it. It is a Milwaukee.

 

[Randy Holmes-Farley Verified Community Expert]

Randy, would a mild citric acid solution for 15-20 min be ok for cleaning calcium deposits (or other things) on it? After that- I want to recalibrate it. It is a Milwaukee.

Yes, that should be fine, IMO.