Natural daily spectrum and intensity vs. fast on/off?

[Nonya]

Has anyone done any research comparing coral growth, coloration and health under a more natural change in spectrum and intensity from dawn and dusk to the fast on and off? Since adjustment of spectrum change throughout the day would be necessary, I assume this would have to be done with LEDs.

 

[blaxsun]

I know my fish don't appreciate abrupt on/off lighting changes, so I'm inclined to believe that at least insofar as all the reef inhabitants (including corals) are concerned - a gradual fade-in/fade-out is preferable.

 

[bobnicaragua]

Based on years of successful T5 and halide use, I’d say corals don’t much care. Fish definitely freak out when the lights turn off abruptly. I’m thinking their survival instincts kick in. They need to take cover before the sharks show up to feed!

 

[SilvermistInc]

I've done a ton of Googling on this, and have found no evidence that there's any real benefit to a ramp up/down. I'm serious. Not a single scientific paper or anything. The only "complaint" I hear about instant switching has only to do with the fish being spooked. Never with the health of the coral.

 

[A. grandis]

Too many variables! Any scientific research or experiment will only define and allow results within the limits of that specific application.
The answer for your question is to understand DLI (Daily Light Integral) and apply to each specific case. It's much easier than you might think!