I read something about how oversoaking some brands of artificial whetstones will destroy them?
I read this about hich common stones fall in this category? I read that about my Kitayama...
Good question -- sorry I'm not the one to answer it.
You might do a little searching on an alternative form of the question: which stones can and cannot live in water?
Some stones, that is, can be left in a bucket of water continuously -- though you usually add a little something to keep nastiness from growing -- and some stones will be damaged by this. That would, I think, answer your question, and I know I have seen discussions of this around these parts.
I'm not sure. I've been told the Bestons & the Bester 500 can live in the water. I've also been told that Choceras shouldn't. Beyond that I don't have an exhaustive list. My process is to start my stones soaking while I do something else (eg shower, get a bite to eat, etc) and come back to them after half an hour.