Ooh, this looks tough. Something that a lot of people overlook is water temp. Anytime you have an enclosed grow like this, it makes it hard to control water temps and alter the res if necessary. Someone with more hydro experience can chime in here, I don't know enough about dwc outside of my research.

As far as the lighting goes, those stealth rubbermaids were designed as fixed light structures. Dont mess with the lights, you'll end up burning them on the light bulb surface.