[Hermie's rule]

I think that I posted on here awhile back because I was having problems with book lice. After I deep cleaned the tank, I think the lice vanished after awhile but now they are back again. Do book lice affect humans? How do I get rid of them? I've heard from some people that they're almost impossible to get rid of. I may have to put my crabs up for adoption I'm afraid if I can't get rid of these bugs. Can someone please help me? Thank you very much.