thank y’all. A crawlspace liner is tapped to sides and a sump pump is in the bottom. They put anti freeze in the bottom hopper to prevent freezing in the bottom under the crawlspace plastic.
I most worried about the walls caving in but maybe that’s not an issue. They backfilled with gravel. A slight bow on one wall but it’s not noticeable honestly. I just don’t want it getting worse
Sand Portland Mix in the majority of the bottom. The deep end is pure concrete in hooper. The walls are polymer with gravel back fill. 10 inch collar and concrete patio around the top.