Let's start with the 3-D rock background. I was inspired by some posts here, which of course I don't remember now, so props to the original pioneers that inspired me.
I used egg crate cut to size, some small dry rocks and black pond foam to cobble this monstrosity together.
That's the first run through, I put wax paper under the egg crate to keep the foam from sticking to the table. Word of warning this stuff sticks everywhere and the color will stick to your hands for weeks. Use gloves.
Originally I made molds to get rock shapes by taking some meltable plastic and covering pieces of dry rock. In the end I found that particular bit to not work so great. I ended up doing most of the fake rocks by hand, using various things to poke holes in the foam once it began to set up. Protip: coat the items with cooking spray or oil to keep them from getting stuck in the foam.
I built the background in two pieces since my tank has a crossbar. I also left an area up top without background as I didn't know what I'd be doing for wavemakers at the time. Originally I attempted to do a wrap around the corner overflows, but eventually decided against it.
Finally, once the foaming was done, I took the two backgrounds and used a spray version of one of the epoxies that some have claimed to be safe, Envirotek. I apparently didn't take pictures of the sand covering phase. It took a couple of coats and I wasted about 10lbs of argonite sand to get the end results. The sand didn't fully cover everything, leaving some of the black exposed, but it came out pretty good.
I originally planned on using magnets to keep this thing from floating away, but couldn't find strong enough magnets to keep the thing down through the glass. I ended up just siliconing it directly to the back glass.
Now that the tank has been in use for a while, I found that the motion of the waves has rubbed off a lot of the sand, especially on top. Eventually coraline will cover that up.
