I use neem oil to great success. Neem Oil does not kill the mites, but it basically retards them and makes them forget how to reproduce. So they will die off. BUT you must reapply again in a couple weeks because it will not kill the eggs and they will hatch and try to reinfest your plant. (I have seen this happen also. My lazy grower firend didn't want to hit them again because they were bigger and it would be more work, and the bugs came back in flower which makes it really hard to deal with since you can't really spray anything onto your flowering plants, let alone a pesticide.) I mix 1.5 tsp to 32 oz of mildly warm water with 1/4tsp of cocowet as the wetting agent. I try to reapply every 2 weeks. I will try to hit them once in dixie cups once in 1 gallons and one more time before they go into flower in 10 gallon pots.
Neem Oil is an all around great add to your garden in general. Neem Oil not only helps preven Spider Mites, but also protects your plants against Powdery Mildew, and many other bugs and fungi's. I share a grow room with other people and I am the only grower that uses Neem. Other people's plants get mites, mine don't even though there are plants with bugs around them. If this doesn't help, you might try some Pyrethrum, but this is a toxic spray and I would not use unless it is a last resort. You can fry your plants if you apply too much (my buddy did it right in front of me.)
We've used azamax also, which helped in the beginning, but the mites came back again during bloom. I am sure with regular application, it will work fine.
If you are going to implement a regimen of pest control in your room, start with cleaning everything and keeping it clean. Then I would use the Neem Oil in a foliar spray. Apply every 2 weeks or so. I would also recommend using a few different kinds that work reliably and safely so as to prevent pest from building a tolerance to anything.
As was mentioned earlier, cleanliness is also one of the biggest deterent to bugs. If you clip branches or pull any leaves, get them out of the grow room immediately. Spider mites will leave dying material in search for plants that are still alive.
