PH testing

[KClark]

I just got a new ph probe for my apex, it reads 8.66, i also tested with milwaukee handheld probe it read 8.2, also tested with hanna it read 7.8. I don't know which one is the most accurate any help would be appreciated. Thanks Kevin

 

[Randy Holmes-Farley Verified Community Expert]

Have you recently calibrated all three with the same calibration fluids?

 

[KClark]

Have you recently calibrated all three with the same calibration fluids?

I have but i have ordered brand new fluids and will do it again when they get here.

 

[Randy Holmes-Farley Verified Community Expert]

I have but i have ordered brand new fluids and will do it again when they get here.

Ok, let us know what they read when done, including the pH 10 calibration fluid after calibration.

 

[Reeferbadness]

I never trust my Apex probes other than Temp. PH isn't a big thing i test for anyways - maybe 2x a year. It's always around 8.4 using a Hanna tester. I would just go with your other tester and then calculate the difference and know that your Apex is off by x %

 

[KClark]

Ok, let us know what they read when done, including the pH 10 calibration fluid after calibration.

I just used the Hanna to Check kalkwasser it read 8.3. The others read it at 12.4. I think the Hanna is not working properly. Weird because I just bought it

 

[Randy Holmes-Farley Verified Community Expert]

I just used the Hanna to Check kalkwasser it read 8.3. The others read it at 12.4. I think the Hanna is not working properly. Weird because I just bought it

It will need calibration even when new.

 

[KClark]

There isn’t a way to calibrate it that I can find. It’s the ph tester using a curvette and reagent solution

 

[Randy Holmes-Farley Verified Community Expert]

There isn’t a way to calibrate it that I can find. It’s the ph tester using a curvette and reagent solution

Oh, that one. They also sell pH meters.

 

[KClark]

Oh, that one. They also sell pH meters.

Yeah I don’t know how to calibrate it

 

[Randy Holmes-Farley Verified Community Expert]

Yeah I don’t know how to calibrate it

You cannot, at least not without some seawater with known pH. It’s an inherent problem with pH kits and the Hanna.