My pool is completely in ground and I am getting ready to backfill. I am going to be backfilling either with 3/4" crushed limestone, or with mixture 3/8"-3/4". Before I backfill, I poured collar around a pool 12" wide, 6" high as per instructions. My question is, do I need to install any drain around the pool, and how would that work, as the whole pool is in ground? Do I need to install a sump pump? If not, what is the point, as the gravel already serves as drain handler. Or am I missing something?