Best crop I ever had was from cheap tomato compost from local garden center, b cuzz nootz from a friend and I never touched the PH, Was using a 400 watt with a hps and an old 250 watt with either a mixed bulb or a MH (I forget) anyway some days I forgot (or couldn't be arsed) turning the lights off (timer ? don't ask) they would have around 2 or 3 days with full 24 hour light, this happened about 3 times. The plants had some big ass fan leaves which were all fully yellow by harvest time. Got 12 oz off 4 plants. Was in a shed in winter with a radiator on and had some windy days, so maybe allot of good fresh air getting blown to them was what made the diff. Sounds like the worst set up ever an I reeled off 12 oz. Wouldn't try it in my shed now a days though, 2 many sadists around that would grass/snitch.