Donít use a black light for your iguana. Most iguanas will put themselves to bed in another spot regardless of the light being available for 12 hours. Put the timer on for 12 hours and have a sleeping spot that is darker and feels safe to your iguana. Sometimes you will find the light is on for nothing because your ig goes to sleep before that. Just adjust the timer so you donít waste bulb life. Iguanas sleep in darkness.