Oops.. And everything! So I'm placing it on my main floor. I will be bracing from the basement, For the weight. I want to make it as light as possible. So instead of have tons of real rocks to make caves I was thinking about creating my own caves out of concrete. What you guys think? Do you have any great ways to do it? I had thought about using styrofoam but I don't want to silicone it to the aquarium, I want to be able to move it around.