Hi, my new (to me anyway!) Rena 210l tank has a lighting unit that slides back and forth on runners attached to the sides of the tank. The tubes are T8s, 1x30w and 1 which I can't read as the info is underneath and the tube is hot! It's a different colour to the other one. Anyway, with these lights, I only get 0.9 wpg and the tank is quite deep (18" from lights to substrate) so I imagine the 0.9 will be even less at the bottom. How can I increase the lighting with this "movable" set-up? The lid is 3 sections of flat metal so I can't attach anything to that... Anyone have experience with this lighting unit?