cleaning practices

[Invigor]

Just trying to get a general feeling what others have to say about this..

I've heard that in DSBs they must remain untouched because over time there's a buildup of toxic bacteria that can crash a tank into nothing in no time at all if it's disturbed. Has anyone had this happen or is it just a myth?

Can it happen in any unmaintained tank, not necessarily just DSBs? Does anyone gravel vac their marine tanks? It's critical in freshwater tanks, but is it critical in marines or does the bacteria keep up with it? How do you keep a sandbed clean when it's made with sand instead of larger crushed coral? Do people rely on "cleanup crew" to simplify tank maintenance?