I'm having my pool installed on April 10th - 15 foot round. The installer said to only fill the pool 1 foot per day not all at once. I have never heard that before? Has anyone heard of that? He said the liner needs time to settle and filling it all at once could burst the liner. But I'm worried because I have read on this website that you never want to leave a pool empty or near empty because the walls could collapse or something? I'm confused what to do? Thanks