If you're going with dry/quarried rock make sure to soak the rock in RO/DI water and test for PO4. Don't ask me how I know
Once it becomes live... and clean, it works great.
Seeding with clean live rock is a good idea for bio-diversity (pods, worms, etc, etc). I know you're trying to keep out the bad, but you also keep out the good. There's more to live rock than de-nitrification.