1st auto

If you've not been giving them any nutes, it can't be anything but the PH... 7 is WAY too high - you need to get down to 6.3 (a good range for weed is 6.0-6.5). I really don't like the color of those leaves but it's not a calcium deficiency or a magnesium deficiency so CalMag is going to do nothing for you. I'm wondering why you haven't started on nutes... You're already in flower and at this stage, your grow is going to need increased phosphorus and potassium plus a whole host of other micronutrients bloom nutes would give you... so the two things I'd recommend is 1) get that PH down between 6.0 and 6.5 MAX and start some bloom nutes pronto... otherwise, you're going to have a poor harvest! (I'd also whack off those off-color leaves and just pay attention to the new growth you get after you correct the PH and start the nutes)... Good luck!