Zoo Med AquaSun® Dual TimerHelps provide natural day night cycle for your fish, plants, or live coral. Dual Timer for Aquarium lighting devices. Top outlet controlled by timer, bottom outlet is continuous. Regulate your aquariums photoperiod with this easy to use dual timer! AquaSun Timers Instructional Video Need an easy to use, 24 hour timer that helps you manage the day and night cycle of your pets habitat? Look no further! Check out the AquaSun Aquarium Timer!