I'm guessing you dont use a ph meter? Or a ppm meter? Youre plants are stretched to the point of falling over. A 400w should be within 8" of the tops. They dont look too good....sorry. I doubt you will get a harvest from those. There seems to be a mg shortage way up to the top leaves, caused by a ph lockout i'm sure.

Lights in the tray are not your biggest prob with these plants. Study up on ph and ppm, its really addictive once you understand all the technical crap, haha. Good luck