I hope you don't mind.. but I must provide some constructive criticism. Well.. this is what I would do with your setup..
I'd try to utilize the walls maybe.. build a corner shelf nice and sturdy and use a stud finder of course. Dimensions could be the width of the tank by half. The shelf itself could be an old barbeque grill cleaned really good set inside a wood frame. A side could protrude down from the shelf to the tank and be roughly 12 inches high in a frame style too with a plexiglass centre for viewing.. this frame side would be mildly supporting on top or built into the groove of the tank. Your lights could sit on top of the grill.. it would essentially be a half canopy, yet it's main support is a shelf for lighting.
just something I thought of. and if it ever needed removing.. all you would need is polyfil, time, a sander and the same colour paint as the walls and your laughing..
Adam



