A word of warning when building a deck from ACQ treated lumber. This type of lumber contains no arsenic, so it's safer to use, but it is also more corrosive, so don't use galvanized screws. We did and our deck collapsed.
We were told by a friend who works in construction to use the hot-dipped galvanized screws to avoid corrosion and collapse. We did just that, and our deck is still standing. I think the ACQ lumber contains copper that is corrosive to other metals.