I currently have a black background reef but when I upgrade in a couple of weeks I am thinking about leaving the new tank background bare instead of painting it. The tank will be up against a white wall. I really love the look of such tanks, as you get that extra depth, fish swimming in air look, and extra PAR. My biggest concern though is that equipment (wavemakers) will be really obvious (though I think if you keep it clean and neat then it doesn't look too bad) and keeping the glass clean. However, I have a holding tank without a black back wall and find that, similar to the front pane, you can have quite a bit of algae build-up before you really notice anything. I did consider using frosting on the back or white paint but I think that really would show up algae!
I'd love to see some photos of your bare-back reefs for inspiration and hear if you have any regrets!
I'd love to see some photos of your bare-back reefs for inspiration and hear if you have any regrets!