starting tank soon

[Aquattro]

Next, I would get dead sand and your rock. I'm assuming you have saltwater in the tank at the correct temp and 1.026 SG. Run the system with just the rock for a week or so, just to make sure you don't have a cycle. Then start adding your cleaning crew (snails, hermits). After that, you could start adding a fish or 2.
Getting live sand from other people speeds up the cycling, but also transfers any disease they may have in their tank. I wouldn't worry about it.
As for a pump, we'll need to know your overflow plumbing size. It's likely that a MAG 9 or 12 would suit your needs. They are very quiet.