I'm wondering if you are burning them....are you misting them with the light on? I'd also check the ph of your soil runoff and see what it comes up as....Don't know enough about soil to really offer anything....sorry.....looks like possibly ph lockout.

Here is an excellent troubleshooting chart.....hope it helps. Good luck.

Revised: The Complete Guide To Sick Plants,pH and Pest Troubles - PlanetGanja.com
Weedhound Reviewed by Weedhound on . Not Sure How do these look, i'm not sure if i have Heat stress, or from what i was told when they arrived on Aug 22nd they this plant is normally light/pale green... 400w MH on 24/7 feeding only water - i think they are too young for fert Misting twice a day Temp - 75 - 84 Hum - 42 - 54% fan blowing light all the time. Arrival Day and now Rating: 5