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