Programming a Save-A-Watt Digital Timer - BRStv How-To
The timer gives the ability to program it for all seven days of the week, in 15-minute intervals. The large soft-touch buttons are easy to work with and the large digital display lets you know what they are doing. The Save-A-Watt timers are perfect for AC power powerheads, lights, fans, or any other type of equipment that you may not want running all day every day.
If you are looking for a timer with a bit more granular time intervals, you may want to take a look at an aquarium controller like an Apex, or a ReefKeeper.