CAL-MAG question, again......

[Wildfan76]

its on upper leaves as well, but not up by the colas, its hard to tell now if its because its at day 30 or so of flower, I think northern lights goes in 50 days or so, I'm still feeding cal mag though and my root ph is at 6.5

[ZigZag]

It might take awhile for the PH to get your existing nutrients into balance, with soil this will take longer. Some recommendations when doing a flush with PH water only is to run 2X as many gallons through your planters as they hold....10 gallons for a 5 gallon planter. I put a plant about two weeks behind doing this a few grows back but it did recover. When did you make the change to flowering nutrients, maybe not enough potassium?
I had this happen with a few plants before too and couldn't get it corrected but like others have commented, discovering why you are having the calcium/magnesium deficiency is the challenge_ because you have to fix that first. If your plant can't absorb the cal-mag you're feeding it then thats not going to make it better. I still got some nice buds from the ones that had those symptoms and for the last 2 weeks of flowering just about all my plants have yellow leaves....probably because I cut off the nutrients about 2 weeks before anticipated harvest....and then I end up going another week or so....maybe I'll get better at judging that after a few more grows. But the stress seems to increase resin an trichome production during that part of the flowering period.