Mine look like that if I mist them too heavily with plain tap water. Looks like salt and minerals left behind from the water evaporating. Usually if you let water dry on any surface in droplets, it will look "spotty."
you could try misting gently with plain water tommorw. It may help.
yes its the only one in coco and I potted to a smaller pot flushed and then started running at full strength nutes a buddy then told me about foiler feeding and said it woild help so I tried and this is what happens