We have recently started a vinyl linear pool install, our excavator had to dig past 42" since some of the area was backfill around our home and he had to dig to virgin soil. So here is the question.. How do you build back the area especially on the shelf in the deep end? We are planning on putting gravel on the shallow end to build back up... We were thinking about forming with concrete on the deep end shelf to place the wall system.. Any suggestions would be great!