I have heard some put 1 1/2" Dow Chemical Blue Board Styrofoam Board under their pool instead of sand. I was thinking of doing this too. I have a lot of it. I install walk-in coolers and freezers and we put two layers (total 4") under 4" of concrete for insulated slabs for walk-in freezers.

I was thinking of using sand to perfectly level my yard where the pool will go. A Tahaitian (SharkLine) 18' x 40' x 54" deep. Then put 2" Blue Board on top of that. I was wondering should I extend the 2" blue styrofoam out a couple of feet around the pools and install the supports on the styrofoam? I thought of using 1/8" Aluminum deck plating under the supports between the styrofoam and the supports. Maybe, say a 8' x 10" x 1/8" under each one on the styrofoam to disturibate the weight some.

Also I am using the plastic pool cove and a Gorilla pad. Does anyone think this will be a good set up? Thanks.
Aranon.