I have a heat pad on thermostat and a ceramic heat emitter on top. I added that when I knew mom was ready to have babies just to bump the heat and humidity for them.

Hydro balls are what people use in the bottom of dart frog vivariums. It makes a separation between the substrate and the bottom so when you add water, the water can pool at the bottom without making it muddy. Mostly for growing live plants in vivs so the plants don't get root rot but they do work great in scorp enclosures as well. As long as you have some sort of screen between the hydro ball layer and the substrate that is. I learned that the hard way.