Quote Originally Posted by j94712 View Post
ok thanks a lot! many great advices! i will treat the whole room and the whole collection. Did not know that I have to treat the racks as well. For the substrate, i use harlan aspen. Just wanted to know if anyone is using it and have no problem with mites?
Yes, do the racks. The mites can crawl out of the tubs and nest along the rack walls and shelves, which is probably why they keep coming back.

I use Harlan Aspen, haven't had any issue with mites. But I also pre-treat all new animals in quarantine for mites regardless if they have them or not.