I'm new to this forum so I'm not sure if this question has already been answer so if it has sorry. I'm having a 16x32 rectangular vinyl pool installed next week. I decided to go with paver stone for the coping & decking. My pool installer is going to back fill the pool with sand & pour 3 feet of concrete up to the top mount coping. I was talking to the guy that is doing the stone work and he recommended backfilling around the pool with either HBP aggregate or clear gravel. He said over time the concrete will settle on the sand therefor shifting the paver stone that is laid on top. Has anyone had this problem? What do most people backfill their pool with?