Also,

If it is a new meter the probe was probably dry.

The readings are more stable after the probe has been hydrated



Joe Sallustio wrote:
> On Sep 15, 6:47 am, wrote:
>> Just got a hannah phep ph meter , set it up and did 2 point
>> calibration with pre packaged buffers....7 and 4.01 according to
>> dorections.after calibration is "locked in" , i tested some tap
>> water , then both buffers...the 4.01 tested just that , but the 7
>> tested like 7.3 . is this normal deviation ?
>
> No, unless it's a 'checker'. The prpbe on that meter is not very
> stable in my experience. Most Hanna meters have an accuracy (or
> precision) of 0.1 pH or better. Recalibrate it and see if it works
> better.
>
> The pHep5 has an annoying habit of shutting down through an auto time;
> if it powers off you need to recalibrate it. There is a work
> around. Just press hold. It keeps it up several minutes longer. I
> wrote a pH meter FAQ a while ago, just search the archives or i can
> repost.
>
> Joe
>