it takes time for predatory mites to breed to a productive level, by the time there would be enough, you'd be harvesting.
if i get mites before flower, i've found that alternating sprayings of spinosad and pyrethin work well, 3 days between sprayings, its killed everything so far.
once a plants into flower, i don't like to use anything but spinosad. spray it three days apart, at least 4 times, and that ought to catch all the eggs and newbies. you're a month away from harvest, keep them under control and it doesn't really matter if you completely eradicate them. just clean your area real well before you use it again, and spray the hell out of it with pyrethin before you put anything back in it.
they come in on your clothes most of the time, so if you have a garden outside, or take walks through the woods, change clothes before you go into your grow room, and it should help with re-infestation