Exo Terra Thermostat 600w & Hydrostat 100wExo Terra Thermostat 600w & Hydrostat 100w With the Exo Terra Thermostat & Hygrostat with Day Night timer you can create a well controlled heating humidifying system that allows you to maintain the required temperature and humidity conditions similar to those found in desert and tropical environments. The day and night temperature and humidity can be set individually. For instance; the temperature can be set lower for the night, while the humidity can