@exnisstech nailed it, but since I had all this typed out anyway, here's my reply hereOne downside is if you like to spend a lot of time on your aquascaping. If you're the kind of person who just stacks rocks and is good to go (and nothing wrong with that!) then it's fine. But if you want to visualize your scape, redo it, break rock apart and glue it together in different ways, then you have a good chance of killing a lot of the bacteria while the rock is out of the water.

Great reply, you're certainly not wrong

I would add a few thoughts here, in case they may help anyone in the future:
You can build your dry rock aquascape and then cycle the whole thing as described previously in this thread (ie in a dark container with circulation).
If you have a larger tank and your aquascape will not fit into a Brute or similar container, consider building your aquascape in two or three (or more) pieces so they will all fit in your cycling vessel. The benefit here is not only being able to fit the rock in your Brute or whatever container, but they are lighter and easier to place in the tank (consider holding 30 pounds of delicately crafted rock scape over a tank while on a step stool). And, they will be easier to move in and/or out of your tank if need be. Many tanks have a center brace that may need to be worked around.
Thanks again for your reply here

