The setup of our Carousel pool was just finished this morning. The installer told us not to backfill around the pool until it was full of water because the sides lock into place as it fills. He also suggested not to go over 10" for fill, preferrable 8". His reasoning was when the time comes to replace the liner the earth around the pool base will push in on the sides. He said it would make his job easier-whatever that means. Hope that helps.