1) pour sand in a pail and wash with some tank water (best if u can do it during water change time)
2) Switch off all wavemakers & return pump.
3) remove all corals that are place on the tank btm. Leave the live rock as it is.
4)locate a spot with the least coral
5) scoop small cup of sand, submerge into tank and pour slowly to that spot
6) use hand to spread the sand across the tank.
Cheers,
James