Oh, I have not used foam because I like my tank the way it is. What I did to rearrange mine was: I found a rectangular thick plastic dish which I put in for water, about 3" (same depth as before). I was able to rearrange the land and rocks, well everything. The reason I tried this was I found I was cleaning the tank often because of the water. To do it right, it takes over an hour (have to remove everything plus jumping crickets). So, I am watching the frogs to see where they go. They're on land and in water both. I wish I had more hiding places and either another cave or house. By not having anything high on the walls, mine cannot escape as easy, they actually don't try. Think I'll see what else I can improve as soon as I get chores done. Any tips on creative hiding places are welcome.