Do all pH meters get this buildup on the outside?

Stored with the storage solution in the cap.

The buffer storage solution is a combination of salts dissolved in water. The water evaporated and left the salts behind to crystallize out on your probe...

It is not a problem, as long as the probe itself has not dried out.

You will want to rinse it well, and re-calibrate with fresh solution.

Yes, if the storage solution contains potassium chloride (which most do). What you are seeing is called "potassium chloride creep". Place some KCl solution in a beaker and it will climb out or make its way between the threads of a bottle cap or sneak through the cracks in a pH meter cap as you see here. Fascinating in that I think KCl is unique in its ability to do this (except maybe for liquid helium?).

My pHep5 does that too, I just assumed the stuff was a strongish buffer so I always make sure to rinse it well and wipe it dry before even putting it in my distilled water before measurement. I always stick the clean/dry probe in distilled water and then dry it again before putting it in any calibration solution or sample (I'm trying to reduce any buffers from carrying over to anything else).

FWIW AJ, I have a couple of ~250 gal heated caustic tanks at work and that stuff is kind of a ***** to 'seal'. It also wants to crystallize (and we use the liquid stuff). It creeps into pump seals and threaded areas/etc. but a combination of t-tape and pipe dope seals threads (like the screw-plug heaters) pretty well. Then we paint the aluminum pump motor face with Super Koropon to protect it when it inevitably creeps past the pump seal.

OK - thanks!