That purple stuff is nasty! Dropped a carb in a container of that stuff to try it out and it immediately started fizzing like an Alka-Seltzer. I took the carb out immediately and it was fine - apparently I missed some of the fine print.
There's a company here locally that makes a product called "Incredible Pink" which I'm sure is like Simple Green, etc. It actually works really well cleaning stuff, but I haven't tried it in an ultra-sonic. It does have the tendency to get a little foamy when agitated. I would like to try an ultra-sonic cleaner here in the next couple of years.