You can immediately improve your grow by getting that pH down! It's WAY too high, my friend... probably why your one girl is not doing well. Cannabis grows best with a pH of 6.0-6.5 .... not 8! And btw, I think what you've done for your set-up is absolutely marvelous. I converted an old funky closet into a "grow closet" by using some left over silver-faced insulation that was hanging about... didn't have enough of it so I used tin foil... whatever works! You're doing a great job - just get the pH down! Get some cheap strips that will at least get your pH in the ballpark ... and if you can't afford to get some pH-Down, use some baking soda but test the water/nutes for the pH before giving it to your ladies...