Well, the ph is a little high for hydro. You wanna keep it between 5.6 and 5.8. I'm not really sure what you're problem is because there are so many things that could cause leaves to wilt. Try adjusting your ph down a little and see if that helps. It might be something as simple as them not getting quite enough of some nutrient or other because of the ph being a skoash too high.

About your lights. How many watts do you have? You need a bare minimum of 35w per square foot, and 50w would be a lot better. How close do you have them from the tops of the plants? Those little guys look a bit stretched to me. Being florecents they ought to be about 2 inches from them to keep the plants from stretching.