Here is a link on the Selcon, which is good stuff in my opinion.

http://www.marinedepot.com/md_viewIt...product=AM1511

Personnally if the tang is eatting well in the main tank I would just leave it in there and just keep boosting its immune system with all the things mentioned. I would give it some time. Flippin it back into the QT might stress it out more. Just my 2 cents.