I think I have a problem. It rained tonight and on the one side where they built the ground up bc the high side was really hard clay and huge rocks (naturally occurring this was below the gravel). It looks soft to me. I stepped on it and it didn't feel firm. Can I put railroad ties or cement blocks around the legs? I am worried even if I do that will it just sink into the ground. Do we need to put some kind of flashing over the top? We have already spent a pretty penny on rentals and paying the guys. I just don't want to throw it up and have more problems. The foam board and sand footprint is exactly big enough for the pool. So the rim where the legs will rest will be dug out so that undisturbed...expect on part where was built up. Thank you sincerely for all of your help.dont remember why. You have a nice prep base there. Ive also seen people try to use pavers and smaller stuff and thats not gonna hold up they crack make sure its not sitting on foam the blocks need to sit on base material