I purchased a 27ft x 52ft round and I am having trouble keeping it level. We used a new sand mixture under the liner. I have a slope in the yard and we used the sand mixture and then we added stone dust. The pool is level all around, but when we add water the pool wall comes out of the track in one area around the slope. What can I do to finally level this pool. The children are getting frustrated and so are the adults, it has been 90 degrees all week.HELP