I don't think chemical leaching is an issue, but I DO know that the foam tends to break down over time on a lot of these foam/rock tanks. I think the guy in the RC thread did just about all he could to alleviate those issues by ziptieing the rock to the egg crate so the whole thing doesn't collapse over time. The foam in that particular case doesn't float for a couple of reasons. 1) the amount of foam is pretty minimal, it's just filling in between the rocks and 2) the foam and rock are attached to the egg crate, and the egg crate is, I believe, siliconed to the tank walls to hold everything in place. You would not want to coat te
LR with epoxy or it will cease to function as water will no longer be able to penetrate the rock. It's just on the foam to help prevent it breaking down. Lowes and Home Sepot both carry egg crate in the lighting section.
