I have 4 plants that are 31 days into flower now. 2 white russian, 1 lemon kush, and 1 northern light feminized. The lower fan leaves on the 2 WR have been turning yellow, and then drooping, and finally turning brown. I think my branches are very weak on the 2 WR also. The LK is now starting also, but the NL is fine. I know my ph is good. Runoff is 6.4 and im using FF Tiger Bloom nutes. Lots of air moving, and my temps get high in the day, so ive switched to running light at night (1000W). I know my pots are a bit smaller than ideal approx. 3-4 g. The NL pot is biggest, and it looks the best. No yellowing at all. could it be root bound issues? Any advice is helpful. The pics are all WR except the all green one which is the NL. I have removed quite a few yellow and brown leaves already.