sorry this is so late but I wasn't paying attention to this thread. Looks like you have a little overfert condition with that leaf tip browning. I guess flush if you want, but since a few days have past since last post and no new pic, it's hard to say what to do. if the browning is getting worse or affecting more plants, you might want to give some more water to dilute the ferts some.
polishpollack Reviewed by polishpollack on . My turn - Stunted growth? Using coco, but this form seems more appropriate than the hydro form. What is your experience level? (first timer, novice, experienced...) Noob (first grow) Your Equipment: .1) Type and wattage of lights. (MH, HPS, CFL's, tube fluorescents, LED's) T5 Florescent 4-2ft tubes in fixture .2) Distance from tops? 4-6 inch .3) Reflector type? (cool tube set-up, bat wing, enclosed reflector, bare bulb...) built-in (fixture) .4) Is there a consistent fresh air supply? Maybe not -- it's in Rating: 5