Young leaves getting crispy and yellow, need help

This is my second time growing plants. First time through was alright, but i feel like i have learned from past mistakes. It was surprising to me to see two of my three healthy plants start to get yellow blotches and the tips get really crispy.
I cut off the crispy areas, but the plants aren't looking so hot. I'm also stumped because the fan leaves on the first node are fine and the top of the plant is fine, only the middle fan leaves seem to be affected.
The plants are about a month old and in a 10 gallon bucket of soil with 4 flourecent lights and a 75 w blue growth light. I have a little fan blowing at all the lights to keep them cool as well as circulate the air around the plants. I also tried to introduce nutes, which is my No. 1 suspect for fucking with my babies. It is just Miracle gro, 12-4-8.
I just gave the two a good washing to try to flush any unwanted shit out of the root system and i hope it works. Another oddity here is that the third plant is growing like a champ, so genetics may be the problem, but if there is any advise from a much wiser grower I'd appreciate it.