I have 7yr old 15ft Round AGP...Having an issue. On pool floor Im noticing a bunch new divots this year. One along wall floor is maybe 5in wide maybe 3in deep , like maybe sand run off. And a bunch of new smaller ones. Am i at risk of some sort of major problem this year?.....I was wanting to replace my liner anyway . In The Swim has a 25 mil 15 round in stock..Now being mid August , can i wait until beginning of next season or does this seem to need to be done now? Help , thanks all.