Its not the PH fluctuation, http://www.growweedeasy.com/ph-fluctuations-cannabis I keep it at 6.0 the entire grow, I also dialed back the nuts, What could it be??
keep a real close eye on them, I looks like TMV . http://en.wikipedia.org/wiki/Tobacco_mosaic_virus Dont bank on it being TMV but never smoke, roll cigs, chew tobbaco around your plants. Wash your hands if you do plan on touching the plants. Cannabis can live through it most of the time,but it can trash a crop. Otherwise magnesium, phosphorus and potassium deficiency are things to check. best case scenario. what are you feeding?