@midEastern,
Nice grow!
Are you sure you have no feed issues though mate?
I don't agree with @Larimar, but I think you might have a small nitrogen issue? Completely normal, yellowing lower growth. I sometimes let my plants develop these symptoms then start feeding accordingly.
I also prune away any necrotic leaves.
Maybe bump up your feed slightly, prune , and then access new yellowing. THAT's just me though.
Cheers.
