Hi! I ended up going with the foam separator idea, partially as a test to see how well it would work. The gravel was for under the dirt as pictured for drainage and possibly extending under the water on the other side. I think it would be too large for a firebelly toad to eat anyway, although at this size it might be better to call them small rocks. Your post reminded me I needed to post my WIP photos. I still need to put in more plants and stuff, but it's off to a good start. Wanna put in some Mopani wood.

Edit: I did kinda drop the ball on the layer operation though...think I might wanna redo it. Not really digging the gravel as a drainage layer Tbh, if I redo it I'll probably buy some clay pellets instead...