let’s say a specific coral requires 4 hrs of light at 100 PAR. I know it’s not that simple but follow me on this one. Would that coral do well at 8 hrs at 50 PAR? Or say, 2 hrs at 200 PAR?
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
There is a principle called Total Light Interval (TLI). Some have written about it, but it pretty much says the same thing that you typed.
However, most articles fail to apply some common sense or any kind of experience. In your example, half the par for twice as long might be OK... but a coral that need 3200 TLI, for example, can do that 8 hours for 400, but 1 hour at 3200 is probably stupid and so is 16 hours at 200. I have never even heard of anybody having any success running 1 hour, nor 16. There has to be some normalcy applied to the hours and intensity, IMO.
I would try and stay in the 7 to 10 hour range, even if the ends are ramping. Some photo cycles need time to get going.

It can really help if you have lights that can do, say 280 PAR and you want to keep high light SPS. You can keep them on for 2-3 more hours and make up some more energy for the higher light ones. It can really work if you use some common sense and are in some kind of normalcy.

