How long can a ph probe stay dry?

This thread almost had the title: "help, sudden drop in ph". Reefkeeper was reading 6.5!!!! I tested up and got a respectable 8 on my alk. Took a glass of water outside, stirred it up and went to measure it and found the probe had fallen out of the tank. Duh.



But in the meantime the probe may have been out of the water for a day or two. Will this have damaged the probe, and if so is the damage permanent? I'm reading at 7.9 now, and I've always been. 8.1 during the day.



Thanks as always,

Helen