Looks like it's likely a
nutrient or root problem.
1. What
nutrients are you using?
2. How are you mixing them?
3. What's the pH?
4. What are you using in the black bags for a
growing medium?
5. What's the nutrient temp?
6. What's your watering cycle?
7. what's the air temp, humidity like?
8. How often do you change the nutrients.
9. How many gallons is the nutrient reservoir, and how many plants is it feeding?