How long does it take the cloudiness to settle after switching from rock to sand .
By rock do you mean gravel? If so when switching from gravel to sand as a substrate it can take up to 24 hours for the sand to settle! However if it is still cloudy after 24 hours a partial water change should help! Also worth mentioning that until the sand has settled I wouldn't turn on your filter as it can really mess up the impeller..
Hope this helps!
Yes I meant gravel . It's already looking better. I did a 50% water change right after .