i have it too ... we did rinse it a little before we put it in, but mine doesn't float or cloud the water at all. It looks very natural also. In beginning it looked bright white, which I liked, but not that its been in there for a year, its still white, just not brite anymore. But I don't have any trouble ... even with a gravel vac ... it just spins around in the gravel vac tube and then falls back down. My loaches are always rooting around in it and stuff.
My only regret is that I didn't put a layer of peat or flourite under it, sine I have live plants.