This seems to be a pretty hot topic on virtually every other fish forum I've been to, so perhaps there are some fellow amatuer aquatic sculptors on here---if not, perhaps with the proper amount of advice and encouragement, there could be!
I got really tired of the plain painted-black background on my previous tank, so when I upgraded to my current 55g I thought I'd try my hand at one of those nifty DIY 3D backgrounds I've seen all over the net. Let it be known that my cement-working skills are virtually nonexistent, and so my initial idea to go the cement-over-foam route failed horribly. (Cement thin enough to get into small crevices = cement thin enough to dry out and flake off despite all my best efforts to keep it wet during curing.) I then instead just used straight Drylok over styrofoam with excellent results, also without the obnoxious fill-and-drain period required for completely curing the cement.
I didn't think to take step-by-step photos of the second prototype, mainly because I half expected it to come out as badly as the first one. So instead I only have one photo of the unfinished background, as seen here:
This is just the foam with the colored Drylok (using Quikcrete Mortar color). Then immediately after installation, now complete with two consecutively lighter shades of gray as highlights:
(Please ignore the ridiculous mismatched lighting going on in this one---I hadn't yet replaced the bulbs the tank came with when I bought it used.) The raised portion to the right houses the filter intake and the heater---the water can pass pretty freely through a gap ~2"x10", which is covered with that plastic screen stuff used in yarn crafts. The oblong rock-type thing near the bottom left hides the air stone, whose line runs down a little groove behind the background and pops out just under the rock. The fish go absolutely crazy over the little spot underneath this rock for whatever reason---it has become some pretty high demand real estate! Most of the other bumps and humps are caves, and I might add, made rock stacking for my cichlids a thousand times easier than it has been in the past.
Here it is with the tank set up:
And I think it warrants mentioning that the background seems to "blend in" a lot better when looked at from further away. (Also the photo looks a little better since the lighting doesn't wash the highlights out to such an extent that they look white, as they do in the closer-up pic.) For reference:
I think it came out fairly well for a first swing at the whole DIY background thing. In retrospect I wish I'd used some browns in the background because the rocks I had in my last tank were all a tawny brown color and looked absolutely terrible, so I had to switch them out for the ones pictured. Excuse the lack of foliage and proper lighting---working on the plant thing currently and still waiting on my custom wood canopy before I'll be able to put my LEDs and whatnot in---the crappy little plastic hoods the tank came with only have enough space to accommodate two little 18" T8 bulbs, so that really has put a damper on things as far as lighting goes!
So...anyone else ever tried something similar? I showed you mine---now you show me yours!