Lumens make a big difference when they are in the proper spectrum. Plants convert chlorophyll a-b & beta carotene into sugars/foods by absorbing light mostly from the red and blue spectrum. I use a 2100k 1000w Plantmax HPS with 8 T5 fluorescents 4-6500k and 4 hortilux UVA/UVB spectrum in a 5'.5"...
You have one of a few problems...ph imbalance can block out ur nutes or slow uptake of certain ones depending on the imbalance of your ph, too high or too low, shoot for 6.5. Over fertilizing can shut down nutrient uptake altogether and cause curled over leaves as can over water. With out...
Ed Rosenthal's book will answer all your questions for 30 bucks. I learned from basically green to producing 21.5% thc .8% cbd. Sour Tangie Crocket's cut.