Hey I planted these from seed, have them under CFLs 24/7. They have been growing super slow but otherwise seem healthy till about a week and a half ago. The fan leaves are turning yellow from the tips/edges inward. I started them on fox farms Grow Big and havent noticed any change yet. The yellowing started at the bottom of the plant and is moving up rather quickly. I dont check the ph of the water I feed them because im on a low budget grow, I give them collected rain water..but im getting a ph kit this week. Please help diagnose the problem and how to correct it...thankyou all very much!!!