HELPP my plants are dying!

i dont have a camera but im trying to get one. but here are the conditions.
about 85 degrees
home made dwc system.
abiut 1/2 strength general hydroponics Maxi Grow.
1 400 watt MH light.
a fan blowing on plants at all times.
ph is about 5.8
there is a mix of bag seed and WW and 1 AK47. all are about 4 inches tall.
i have one WW in soil beside them that is growing alot faster than htey are and the ones in DWC are dying. it looked like a MG of N def. but i thought i corrected it the bottom leaves started yeowing then the veins turned real dark green in some and other are just turing yellow and light green?
ANY IDEAS????????

alf

your burning them!! half mixture of ferts is too much. im assuming they are seedlings. dont fertlize the seedlings at all till theyre in veggie mode. then you can add your ferts which is usually a teaspoon per gallon. read the box and i usually go with a little under what is recommended usually cuz most fertilizers arent made for the mj plant.