I have tried to use sand to no avail in my freshwater tanks and had the problems that you bring up with the sand in the water and filter concerns, but from my experience with live sand in a SW tank, it is a totally different thing and is very good at settling out and does not kick up too easily in my tank at all. Even when I am messing around a lot with my rock or cleaning the tank, the sand settles out really quickly. Plus, it would completely undo the 'live' part of live sand to rinse it out so you can skip that step. The fish are also pretty used to being in sandstorms created by hurricanes and stormy seas so they can handle it, especailly reef type fish. Hopefully others can back me up on this for you. It must be something to do with the salty water or something that makes the sand act totally different in a SW tank than in a FW tank.
