Rinse the HydroBalls well to remove any dust. Place a layer of HydroBalls in the bottom of your terrarium. Fill to a depth of 2 inches.
Place terrarium substrate mesh over HydroBalls to prevent mixing with substrate. Substrate mesh should be the same size as your terrarium bottom.
Add substrate suitable for the specific reptile or animal you are keeping in the terrarium. Different species require different substrates, including various types of wood chips, moss, sand or gravel. If you are not certain, consult a professional at a pet supply or reptile specialty shop.
Add enough dechlorinated water to create a shallow layer of water in the bottom of the tank. The amount of water added will depend on temperature, humidity level in the room and type of reptile or amphibian in the tank. You will need to check daily to make sure humidity in the tank is adequate, and add water when necessary. It is best to have a humidity gauge in the tank.