No Cal/Mag , although I do have Revive , which should be a similar product. Maybe I should try it out . I’m running COB leds , wasn’t aware of that , thanks for the tips !!Could very well be the case. High doses of P tends to inhibit uptake of either magnesium or calcium (can't remember which). I see you're also using LED's. Have you been supplementing with any Cal/Mag?...LED lights tend to cause plants to use more. But if high phoshprous is the issue, adding all the cal/mag in the world won't help, only reducing the phosphorous will. So yes, I'd start there and observe for improvement, which will take the form of the symptoms not spreading anymore. Severely damaged leaves likely won't recover.