has he been soaking much? a month ago i had to deal with a mite problem and we successfully used mite-off. it worked very well, just emptied out the tank, washed it out, mite-off enclosure and Aza, substrate change to paper towels, repeat in 3 days to get the whole life cycle, non-feeders that weren't killed in the first round. it worked well and she is clear of all mites. i always sprayed some mite off surrounding the enclosure so there was no chance for stray mites to aimlessly reinfect and they starve in a short time if not on a reptile.