I wouldn't worry to much about the lowest fan leaves
the rest of the plant I think looks pretty dark green
as long as the top 80% looks healthy
a small amount of N def is acceptable (if that's what it is) during flower and better than too much
some times its just not enough light getting down to the bottom of the plant to keep it healthy... I usually cut the lower spindley growth off at week 2 of 12/12 when the stretch is about over
are the grow lights on in this pic?
id like to see a picture of the entire plant and some shots of the top canopy with the grow light out so I we can see the natural colors
2 things, the lower leaves doesent get too much light. I see signs of little nute burn. give them just water for the next 2, 3 feeds. the plant is looking good.