Timers:

Timers help regular the light cycle of your aquarium. This is especially important for plants and corals. If you have a fish only tank, it will also help your fish regulate their nocturnal habits. Timers are recommended for any type of aquarium setup and will benefit any aquarium. Timers help more accurately portray a real ecosystem with light that is consistent.

Lighting cycles should replicate the natural rising and setting of the sun. There should be at least 12 hours of light on your aquarium during the day for proper coral and plant growth.

Dusk to dawn effects happen when fixtures have multiple colored lights that turn on at different times to progressively make the fixture brighter, then the process is ran backwards to simulate dawn. If you have 2 actinic lamps and 2 10,000K colored lamps, to simulate this dusk to dawn feature you would put each lamp on different timers. First the Actinic would come on, say at 7am, then around 8 or 9am the 10K lamps would come on as well.