#rock

I know light diffusers and Styrofoam can be used to pad rocks in an aquarium, but can foam? I have a few pieces of foam that I'm not using.. two are 2 inches thick, and flat, and one is also 2 inches thick with egg crate divots.    

Hey guys, I am in the process of setting up another tank and I had some questions regarding some items I have found at cheaper prices than pet stores etc.   The issue I am concerned with is that they are not safe or not the same as the other items usually used in their place.   First is the...