We are putting up a 15 x 30 steel wall pool. We've already purchased a foam cove. Our soil is quite sandy so we're thinking we can get away with not bringing in sand if we use a 1/2" or so of sifted soil to cover the inside framework and then put down a layer of rigid polystyrene foam insulation to make a smooth bottom. We plan to fit it very tightly inside the pool walls and tape with lots of duct tape to avoid any separation gaps. Home Depot carries a 1" blue Polyshield insulation. It costs $9.63 per 4' x 8' sheet. They also have the 1/2" Owen-Corning pink insulation board for $13.76 per sheet. (The 2" isn't available here and would probably be out of our price range anyway.) The blue sheets weigh 1 pound and the pink weigh 2.7 pounds so I'm guessing that the pink insulation is much denser. The pink insulation description states that it is impervious to moisture. I don't know if this is the case for the blue insulation. It would cost about $65 more for the pink than for the blue. Has anyone used either of these? We don't have money to burn but this will be a permanent installation so we want it to hold up for a long time. Any thoughts on whether the pink is worth the extra money or would the blue work just as well? Thanks in advance.