A tip on the live sand if you are going to be adding it to a tank that has water and fish in it already. Drain off as much water as possible there in the store from the sand before they put it into the plastic bag to send it home with you. When you get home, just slowly put the whole bag of live sand in your tank and sink it to the bottom (if it is a regular fish bag with live sand they have had to scoop out for you) when it is on the bottom of the tank, use a razor blade or other sharp implement to slice the side of the bag open, and gently allow the sand to come out of the bag with your help. This will minimize the dust and debris that gets up into your water column, so that you can still see to work in the tank.
If the bag is one of the pre packaged bags that you have bought from a shelf, I wouldn't sink that bag into your tank, because who knows what might have gotten onto the bag.