hey man, what you're seeing is a calcium / magnesium deficiency. I find this quite common when using LED (I guess with the full spectrum, it's a lot of the plant?). I plan to put kelp meal into my soil mixture next time around as I only have about 4 weeks left until harvest. I would say you have a couple weeks left until harvest, little bit of amber and I'd chop her down (say 2, 3 weeks?)...to give any fertilizer now I feel is a little late.
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