@Wopadobop
I think your "3d" design is just complicating things more.
And even more if your gonna place the whole unit IN the tank or sump! Lighting should be waterproofed and be roubd, which should be fine if you used ledstrips but not so much if you want to use hp leds...
In my opinion 2d is the only easy way to go, but who knows maybe the algae will grow like mad in there!
Why not give a jbj fuge light a try? From inside the tube and leave the outside as is?
My 2ct
Jb