Which size sand to use?

[hbo1976]

Is there a preferred sand to use on a reef aquarium? I think there's like 3 or 4 sizes to chose from:
1- extra fine- .5 to 1 mm
2- fine- 1 to 2 mm
3- coarse- 2 to 4 mm
4-?
Does it really matter what you get?

 

[Rick]

The shallower the sand bed the smaller the grain should be. Up to a point, if you had six inches I still do not see using a very coarse sand or crushed coral.

 

[kwl1763]

Small as you can get period. If your SB is shallow you'll have to use the small stuff to get enough bacteria to colonize. Larger you can go bigger but honestly there is no reason to and in my opinion the bigger you go the more potential issues you have! Slightly larger might help prevent sandstorms but usually once the bacteria weigh the sand down you won't have issues unless you have a sand stirring fish or something like that.