poulverized limestone sand bed dust bowl !!!

[mr_anderson]

so I decided to go with a 4" deep sand bed. I went with poulverized limestone since it was very cost effective. After rinsing this stuff out 3 times I placed it into my tank already filled with water. It has been 5 hours and the smokey water looks like its not settling too fast. I have shut down all powerheads.

how long does it take to settle?

should I be worried about the thin layer of dust that settles on the top of the sand bed?