[Sk8r]

I would add, for people doing this with acroporas, test frequently during the dark period. When the algae dies, IMHO it's going to release its mineral content back into the water, because I can't think where else it could go, and depending on the size of the problem, that can be a lot. I'd advise the skimmer should be in good trim and it might not be a bad thing to run phosphate uptake media, plus polypad to take up anything else I'm not sure of...

I do have a potent refugium, 40% of my tank size, with a lot of cheato and live rock and sand, and it keeps its regular light cycle while the tank is in darkness.

Note: I was having rainford goby troubles, because my tank was TOO clean, so I started trying to provoke some cyano, which they will eat, along with hair algae, by putting in phosphate and exposing the tank to indirect sunlight. Couldn't do it, and to my great regret, I lost the fish, which will not eat anything else. The only thing I can raise now is film algae and green plating algae. So now I'm about to do the dark treatment again to get the tank to release what I pumped into it. The sand is already white and the caulerpa has already died out except in the refugium, where a little came in with the cheato.

Clearly this set-up is going to be too clean for the little gobies, but the acropora is doing all right.