do you have fish in there?
if not, don't worry, it will settle, but if you have fish the visibility may stress them, i have never added dry(not live) aragonite, without dust storms, with finer particles they are hard to avoid, the only time i did not have a dust cloud was when i use ls, as far as rinsing goes, if you have no fish, you are probably better off in not rinsing, it is only sand dust, and will add to your bio filter(when it becomes live), the quickrete is heavier than aragonite, but it is still only sand particles, and won't hurt anything (except for stressing fish), but it should settle, our first tank, took about 2 or 3 days to settle out