I use carefresh as well. I have my hammy in it, and I use it my hedgies poop pan (because it is white so I get a good view of his messes
). I've never had a problem, but I don't know if hamsters get mites? It is concerning though.
Just so I understand - did your rates get a rat-specific mite from the carefresh, and now they are carriers of it? And it won't affect hedgehogs?