I was GOING to say she looked like she needed more nitrogen than her sisters... but you've tried that.. so here is what I WILL say:
Aside from her color, she looks to be in magnificent health ... I had one grow of 3 plants of the same strain where one of the ladies was steadfastly lime green throughout her life no matter WHAT I did for her... I just decided that's the color she wanted to be and stopped fussing about it... it was SHE who actually gave me the largest harvest of the 3!! So fiddle with the nitrogen a little more if you really want - but honestly, with the way she looks, I wouldn't stress about it all that much because she DOES look fantastic... albeit a little lime green!
Good luck!