Hi Pipling...welcome to BYC!  No such thing as a moronic question...except those you don't ask!  
 
 
There isn't (to my knowledge) a specific brand name for DE.  Check with your feed store...ask for food grade DE and they should know exactly what you mean.  It's not terribly expensive and a little goes a long way. 
 
Clean out the whole coop, then when you put the bedding back in, sprinkle some DE on it and sort of stir it up enough that it's not all sitting right on top...the chooks will take care of the "real" stirring as they scratch.  Also put some DE in their dust bath and mix it just a little bit.
 
DE is perfectly harmless on the skin or even eaten...the only danger is inhaling it.  So, make sure you wear a mask when working with it and take care that the chickens aren't downwind where they can breathe it in.
 
I found mites on mine as well, and did just this.  You can actually dust the chickens, but I found that just having it where they get it on them was sufficient.
 
HTH
Mickey