I havent checked the ph yet, just ordered some solution ( just cant get to a store that carries the stuff due to work ). The temp in the grow box is good. the bulbs are warm to touch. The yellowing showed up last week after I let it go too long without water. I ve since come to the conclusion that fabric pots need to be watered evrey other day ( I found the yellow after 3 days between watering ) thanks goodness most of the plant looks ok and it wont be a total wash. I hve been using fox farm trio on this exclusively, I also add a little canazym and bud igniter twice. I know my baseline tap water is a ph of 8. I had read that ff droped your ph some so i just mixed it figuring that it would put my ph in a good range ( i know, it was stupid ), I have since learned ff drops ph alot, leason learned.