Hi..in process of selecting pb for my semi in ground aquasport...looking at 15x24 ..had a 15ft aboveground round pool..I had used a 1hp Hayward and sand filter..new pool gonna be 3ft in so pb suggests self priming pump..also back washing has been issue because of garden behind pool...so with new build I thought of burying a backwash line ..but I do have pavers..pb suggested cartridge filter and said I wouldn't have to backwash...question is anyone have some ideas..at least models,prices,do they make a cartridge system with self priming pump...thanks