how long for sand to settle?

[Derringer]

You Will get cloudy water every time you do a >50% WC in a tank with sand

I have never gotten any clouds or even a hint of cloudiness when doing water changes. In fact when I added the sand for the first time I never had cloudiness.

If its still dirty after a day, I am going to guess the OP didnt rinse the sand well enough if at all.

What you need to do is start doing a continuous water change until it clears up.

 

[feylind]

Depends on the grain size on how long it will take to settle out

 

[Cory Keeper]

When I changed over to moon sand, I rinsed it best I could, then put in the tank, waited about 2 hours or so, let all the big grains fall to the floor, Turned on my filter, It cleared it up in no time flat .