thanks for the input guys.
mike: no photoshop, this was when I first setup my tank two years ago, before it got a black back, then after. It's just one of those "stick" on backgrounds that always has a million bubbles that you have to try to get out.
I've had no problem keeping it clean, yesterday just spent like half an hour with a kent scraper blade, by hand, to clean off the coralline and stuff. The problem is the vortechs have tons of coralline on them... I'll probably pull them out and run them through vinegar.
The wall behind it is just white, so not that interesting I guess...