my growing substrate is hydroton clay grow rocks, in 3" net pots. i also have placed three 6" fans on the inside. my problem is that my plants are 3 weeks old and two leaves at the bottom are completely white and the set of leaves above them are yellowing out leaving dark green veins and burning at the tips. the inside of my phototron stays about 80 degrees farenheit so i don't think its heat stress. i have plenty of pics but do not know how to post them. Any feedback would be Highly appreciated.