wow! thanks for the feedback!
yes, the probe is definitely covered with a layer of dirt.
The pen is set for two step calibration. I'm only concerned, because when I put it in 4.01 it displays 4.40 & it takes a long time to establish that.
I need to make sure the water ph = 5.8, so you see why I have concern
thanks for the tip
I'll try cleaning it off, hope this will help