DarkHorse
I don't know how many pounds I ended up with since I reused a LOT of old rock from another tank. I am guessing I ordered 40 pounds and provided 60 pounds myself.
With the rods the whole build is a lot more 'airy' anyway so you get a lot of surface area without having to have a lot of rocks to stack on each other.
I used Pukani. Key Largo will be a little heavier.

Lol@ Erik
I had to photoshop it to envision what it would look like with 500 pounds of sand around it. The structure itself seemed so tall (until you bury a third of it in sand).
Then when I added the sand it was still a little shocking.