When it comes to illuminating your aquarium, it’s not just the type and intensity of the light that’s important, but also the length of time your corals and photosynthetic invertebrates are exposed to that light. For many aquarists, an 8 to 12 hour lighting schedule is really common. After all, corals receive at least this amount, if not more, on natural reefs. That said, it’s also perfectly fine to increase or decrease the length of time your tank’s lights are on each day to better fit your needs. In fact, some reef keepers have reported great success with shortened photoperiods, and some go to extremes one way or another with mixed results. Some have even reported that regular and lengthy periods of no lights helps spur coral growth. That may or may not be true, as almost all evidence within this hobby is anecdotal at best, but it’s important to tinker with the various water parameters and photoperiods to find out what works best for your aquarium.