I am installing an INTEX 18 x 9 x 52 above ground pool which they recommend and ship a tarp to go between the ground and the pool liner. From what I've been reading about the gorilla pad it allows condensation to go down into the ground which is a good thing. and foam and I would guess a tarp would cause condensation to accumulate under the right conditions. So should I install my gorilla pad directly onto the ground and forget about using the tarp? Also the ground I am using is wood frame, crushed granite, with a layer of compacted morter sand. I was concerned about washout from hard rains here in arizona in the summer. So thats why i'm still concidering using a tarp to keep my sand under the pool. Maybe I should just put the tarp on the sides of the pool where the sand would be exposed? What do you think?