If it's fresh FF soil your using also, you don't need to add nutes for quite some time since it's already loaded with bat guano, worm castings, etc. I believe Happy Frog does the same. That could be it. You should still get rid of the mylar on the bottom though. Even if you are just using CFLs. It looks like you may possibly have an N deficiency. But when you get your pH kit tomorrow, you can fix that. Your water is probably pretty alkaline. Also, I've been using FF hydro nutes on my Hibiscus for a while, and it seems to be pretty strong. I started at half strength and it seemed to be too much. But then again, apples to oranges.....