Hi firstpool, and congrats on becoming a pool owner--you're gonna LOVE it this summer!!

Forum traffic is very slow this time of year so it may take several days before you get useful responses to your post. I have zero experience with AG pool foundations, so I'll defer to the others to help you with your questions, but I at least would put a sheet of vinyl down under your pool to help prevent weeds, rocks, etc from penetrating your pool liner from the bottom. There are some posts around the forum that may be helpful--try the google link in my sig to search for pads under AG pools.

Here's an old thread that might help: http://www.poolforum.com/pf2/archive...hp/t-4488.html