Mate. Just cause one or 2 leafs turn yellow doesn't mean anything. If you had a nitrogen issue or any issue for that matter you'll see it on a lot more leafs. And, as you can see, it's all turned one color, not spots, no leaf degradation. If you look at my hydro you'll see the end leafs are like yours too. Its really nothing just the genetics of that plant. They are fine, they don't even have to be removed but best to, if you start messing with stuff just cause you see changes on 1 or 2 leafs you'll make it worse than better, trust me. I was like that too, when first starting, you'd be surprised at how resilient your plants can be, best to keep the course and wait, espically when it's the case of the leaf being a uniformed color and another thing, no matter if you had the best nute in the world, you wouldn't get that to go back green unless it changes color cause it wants too, understand? It's a living thing, like ppl, we get deformities/birthmarks. If you had of kept the course you wouldn't have burned your plant. Which were/are excellent looking, cause when you said nitrogen issues, I was like, WHAT, WHERE. lol. Your grow looks great pal. Keep it up. Oh, and if I were you I'd really consider switching to 12/12 they are autos, see how it's already growing buds and you haven't even switched to flowering. You are just wasting energy, and thinning your bottom line.
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