We bought a used 27' Aqualeader pool. Looking to install it ourselves to save some cash. Everywhere I have looked says you need to sand as a base over your soil. My problem here seems to be that I have no soil, its all just sand and rocks. Most of our yard was also fill from the hill across the road that they knocked down to make a more level yard. We can barely get grass to grow because there is nothing but sand. I guess I am concerned about the sand washing out and the pool going out of level. What would be the best way to prepare the sight, especially since we want to do a 6 foot expandable liner? Are there any precautions we should take?