FWIW and IMHO I started posting in 2003 when dsb's were the in thing. Bout 2-3 years later there were reports of DDB tanks crashing. With all the usual rationalizations of keeping the sand with worms and stuff.curious why a dsb i thought they have been pretty much abandoned in the hobby
I speculate that a dsb uses anaerobic/ anoxic bacteria to reduce nitrates to nitrite and then nitrogen gas. And if not working correctly nitrite to ammonia. Personally I don't like a system the converts nitrates to ammonia. But that's just me. Not to mention possible sulphates and stuff.
So when working correctly at the surface of the sand you have low oxygen, nitrogen gas, and phosphates. Which are exactly what cyano bacteria need to use nitrogen gas for their nitrogen. So when working correctly your nitrates lower, things are going great then all the sudden here comes the cyano bloom. All over everything.
So what I noticed was that DSBs fell outta favor with more and more emphasis on macro algae in a refugium. After all, the macros consume ammonia (when available), nitrates, phosphates and carbon dioxide while returning oxygen and fish food.
Which is why this old planted tank guy prefers using macros or other algae to balance out and stabilize the system.
What being said that with skimmers, low bio loads, and even water changes it does seem possible the plant life action of the corals can have the same effect.
But that's just this old guy's .02