You set a time for night mode then it will automatically switch to night mode everyday at that time. You do this by holding down mode + set at the same time, when the LEDs start flashing hold down mode + set again. Then the vortech is programmed to go into night mode everyday at the time you set it. You can then go into configuration mode and set how long and what speed for night mode. The stock setting is half speed for 10 hours, but it can be changed to whatever you want. Consult the manual for that.
