Some types of sand are cloudier than other types. Non-live sand can be rinsed to remove those little particles that always occur, but with live sand you can't rinse it ahead of time, so the particles go right into the water. If it is horribly cloudy, you can try doing a large water change which will physically remove the particles. Or you can set up a cheap crappy filter with a bunch of filter floss (or similar) to filter some of it out. Otherwise, it will eventually settle. It will settle more quickly if there is less water movement, but then again once you put the powerheads back it'll just blow those settled particles back up again. Do you have any rock and/or other filtration going on right now?