It'll have to be used in our workshop, so if i must go Chinese, it'll have to be high end Chinese. As for the flux, it's rosin, so IPA will probably be needed.
See, my worry isn't the actual reworked stuff. I've never been careless with cleaning off flux. It's just sometimes I want to put some lightly liquid-damaged boards through an IPA containing bath.
Have you ever DIY'd a bath? How involved is it?
I haven't DIY'ed a bath, but it shouldn't be that involved. Driver board, timer switch, and the transducer, and perhaps a heating element if you want/can, and that's all that's in a basic unit. Digital control could be added as well.
In my case, is I'm limited on tooling (have a small oxy acetylene torch, so I might be able to solder up mounts to a stainless restaurant pan with some acid core silver bearing solder), add the electronics, and stuff it in a box.
If you're looking for a professional unit, you might take a look at Branson (can find them on All-spec.com). Not sure of the size, but if it's a standard ATX, and one board at a time or so, then a 5.5 gal might suffice (19.5" x 11.5" x 6" tank; ~$1750). Otherwise, you'd be looking at 10 gal +, depending on the board count (to get the right diminsions).
BTW, they operate at 40kHz, and are made in Mexico.