Back to the mite issue. As others have said soaking will do nothing to get rid of them. It will provide some temporary relief at best. You really need to either get prevent a mite or, if you can't get prevent a mite fast enough, Lice Bedding spray will work just as well. I don't know if there are walmarts in china, but something like this with the active ingredient 0.50% Permethrin is what you want: http://www.walmart.com/ip/Equate-Lic...-5-oz/10324555
I wouldn't worry too much about the wobble. It sucks that he got a bad wobbler, but if he chooses the keep spiders it is something that he will have to deal with. From his size, it's obvious that he has been eating so I am sure once he gets the mites taken care of he will eat just fine for them