hey man, ive been haveing the same exact problem as you. i dont know what it is either. it was fine and then all of a sudden theres these little yellow dots on the leaves right? then it slowly turns yellow and falls off. i am also experiencing yellowing around the buds. i dont know what the hell it is. my leaves are also curling under. i dont know why, i fugured overwatering maybe but, like urself, its not possible. i will join u in your quest for help, as i could use some too. im using a 175 watt hps, with 2 of those high output energy efficient flouros. how far away do u keep em? i assume u grow in a closet as well?