I just bought a bag of this sand for my 10g dwarf puffer tank, and I didn't know about rinsing it. This is the small grain sand you speak of, and I got it at PetSmart.
It's still cloudy after 3 days now. Do I need to break the whole tank back down and rinse this stuff for it to clear up? How do I do this? The tank has not been cycled and is unnoccupied at present. Info would really help.