No stone was used at all in my build. But my ground is very hard like total clay at that depth. My builder said there is no better base to build a pool.
WOW Jimmy. I never even thought about doing it this way. Thank you so much.You will use support tubes filled with concrete when you pour your collar. Cheap 4" drain pipe is perfect. When you pour collar put a bunch in the area you will build waterfall and cut them to height of top of wall minus 2" ahead of time and fill with concrete. Put some 2ft long pieces if rebar bent like an L in top, 2 per pier. Backfill with 3/4 stone that's the right way to backfill a pool. When you are up high enough form a pad around your piers and pour a small slab 6" thick encasing the rebar tieing it all together to the size u need. That's the only way to guarantee no pushing on wall or sinking in future. I've repaired many waterfalls on liner pools done the other way. Heavy stones and blocks near coping push down and then they push the walls out over time if not supported.