With the Eheim Dimmer Day & Night for Eheim classic LED it is possible to create sunrises and sunsets automatically in your aquarium. You can control and set a day cycle with sunrise and sunset and a moonlight at night.Eheim Dimmer Day & Night classic LED+ for natural lighting conditions in your tank+ control of the Eheim classic LED daylight, plants+ automatically running sunrise and sunset+ choice of start time and lighting duration+ brightness adjustable+ moonlight at night+ only for Eheim classic LED+ capacity: max. 1x20 WProgramming of Eheim Dimmer Day & Night classic LED:The appliance is pre-programmed to a daily cycle of 12 hours. The moonlight switches on after 12 hours expire (medium brightness). You can program the appliance accordingly for an individual daily cycle (2-24 hours). The appliance does not include an internal clock. Therefore, begin the programming of the desired sunrise starting time. Begin the programming and increase or decrease the number of hours in the dail