These are my backgrounds. The first pic is my freshwater tank with a mirror background. I had a glass co. cut the mirror the size of my tank and I siliconed it on. It makes the tank look twice as big. It's like the mirror effect you get when looking through the front of your tank at the side glass. The second pic is my saltwater tank. This was after I first put in my live rock. Now I have rearranged things and got a little more coralline growth so it looks a lot better than this pic. Anyway, for this background, I tinted it with a dark mirror smoke tint for cars. It also gives a mirror effect although not as dramatic as the actual mirror. I really like these backgrounds because they add depth to the tanks. Before anyone lectures me about a mirror stressing out my fish, I have had no problems so far. I've never seen my fish bump into the glass try to get at the reflection of itself. I guess you could have a problem if you had a very agressive fish, but the fish I keep are for the most part peaceful.