Pics are too blurry, could just be calcium from the nute water splashing. Or calcium from tap water they used to mist. try wiping it off with a damp cloth.
I've sprayed it most recently and with 30ppm filtered water, I put it in last week and haven't sprayed since. I just checked them again and there's fuzz on the leaf. So what do I do? pull the plant? All the same clones? All the different strains?