Hydroton makes a great bottom layer in a false bottom tank or as the substrate covered with leaves or moss. It provides a place for water to go after being misted in the vivarium, while wicking just enough moisture to keep your substrate moist, but not wet. Maintaining a small volume of water in the bottom of the vivarium helps keep temperature and humidity stable. Hydroton also makes a great hydroponic media, for culturing plants.

To figure out how much hydroton you need, use this formula:

Inches deep / height of the tank (in inches) = hydroton ratio

hydroton ratio X number of gallons = Gallons of hydroton needed

Gallons of hydroton needed X 4 = Liters of hydroton needed

Josh's Frogs recommends using 1 1/2 to 2 inches of hydroton in the bottom of vivaria.