High humidity will cause em to pop like balloons. Also, when spraying, you'll need to hit the entire underside of the plant, every leaf. You'll also need to sterilize the grow room and fog it before starting another crop. Spider mites are a bitch. It's why I never use un-sterilized or cheap soils.I like that you remember the number of times you have grown herb
Isolate your infected plants! Use a 1:1 mix of water and as pure as you can get alcohol. Grain alcohol works, try to get as close to pure if you can. Spray each plant focusing on the bottoms of the leaves where spider mites tend to hang out.
I have read that a high humidity for several days along with frequent misting can actually "drown" the mites.
If all else fails, time to fog the room.