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Re: pH meter calibration

> Can you use distilled water to calibrate a pH meter at 7?
> Thanks
> Sherlock Wong

Sorry, Sherlock.

Not a chance. Distilled water does not have a pH of 7 (atmospheric CO2
drives it lower) and it has no buffering. [Measuring distilled, DI or
even RO water pH is generally not worth the bother, as results can vary
wildly, BTW.]

You need a solution that has been accurately buffered to pH=7, or the
tiniest contamination from your probe will make the pH read almost

Frequent calibration checks *are* a vital process, particularly with the
inexpensive probes we use, and our aquatic environment. Buy buffered
solutions, tho.


Wright Huntley, Fremont CA, USA, 510 494-8679  huntleyone at home dot

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