Re: False bottom vs Hydro
I've always used the expanded clay balls, and in some tanks I've found the springtails prefer to build their colonies in that layer (but not all).
My original reason for using the clay balls was surface area for microbe growth, though i have no proof whatsoever of the benefits.
I now suspect that the clay balls have an added benefit for the way i design my tanks. Each tank i build has a small, shallow water area, and i have a very small pump that circulates the water in the drainage layer. The clay balls provide a filtration and diffusion effect that ensures the entire false bottom is circulated and cleaned. This results in my water areas being quite clear.
I realize this is not applicable to most folks, but if you want to provide low maintenance water access to you frogs, it may be worth considering.