I'd also think about the fact that these plants obviously were doing quite well (big healthy leaves and plant despite current issues) so that makes me SERIOUSLY wonder about the possiblity of rootbound plants......They do look a smite worse and no better.....we should have seen some improvment by now.

Colour you need to realize that with plants MANY symptoms MIMIC each other. Often times diagnosis is figured by trying things one by one and seeing what works. Welcome to hydro!

PS....My personal thought....rootbound at this point......they DO show defs....but I don't think that is your real problem right now. How do the roots look?
Weedhound Reviewed by Weedhound on . Deficiency/Toxicity symptoms in hydro plants, help Literally, no. -DWC -T5 Flo -70-77* F -34-44% RH -Apprx 5th week in veg. -Fox Farm 3 Part w/ LK and CM+(alternating at res change) apprx. 10ml per 1.5 gallons / 3-5 ml CM+ and LK -Distilled water Rating: 5