I'm not totally sold that you have an infestation. Look on the underside of the leaves just as the light comes on, if you don't see anything and it's widespread to a lot of the plant, then you don't have mites.
This looks like your ph got away from you, too acidic, I'd say. After you mix certain nutrients with your water, you obviously test the ph, but you need to come back a couple days later and retest it, because it doesn't always stay put. Even regular tap water acts like that. The R/O water mentioned is great, I'd do it more often, but I'm sick of hauling 5 gallon jugs around and refilling them. If you have like 4-6 plants, 5 gallons lasts quite a while when they're small, but once you start budding them, seems like you're refilling the jugs twice a week. Now, I switch it up, use tap about 2/3 the time. Sorry, went off there.