This is a photo of the upper tier above the caves I built. You can only see about half, which is the half I split to house my 3 juvenile reds. On the right you can see a window I built into the cave wall on upper tier. This is on the adults side, hoping I can get eggs in there and watch them hatch naturally. I probed 6" deep behind the window and its a constant 28.5/29°c , so should be good.