Our pool is on a sand bed but we added the blue foam insulation panels, taped together with Gorilla Tape, then overlayed with a Gorilla Pad...we have the nicest pool bottom ever! We got the idea on this forum! Everyone loves our pool!
If it was mine I would just go straight to xps foam, the thickest your pocket book likes. Go in your chosen box store and put the thinnest you want on the floor a stand on it, that should give you a idea. You can also level with sand underneath the foam if your concrete is sloped
Too late! I just went to harbor freight and picked up a 19x39 tarp on memorial day with a extra 25% off for a grand total of $40. I doubled it and set up the pool. Borax, bleach and some cya for the intial startup and whee! --We are two months ahead of last years start!