Look at Dr. Zymes Eliminator.........many people rave about it. It's citrus based and supposedly effective up to flowering. Only spray with lights off and temps below 80 degrees. You can wash it off, along with the dead mites, after 1 hour to minimize any plant issues. Apply with warm warm between 70-90 degrees and a pH between 6-7.
I would try to lower temps in the room, as cool as you can to slow their reproductive cycle down. Pick off any and all leaves that show mites or damage. You can also apply vasaline along the main stem which won't hurt the plants but will stop the mites migrating.
