I need a new cleaner for my above ground pool. Have had 3 "pool rover" in the past, frist one worked good the last two not so good. I want a good one that will last, but most of the ones that are recommended are for in ground pools. Some in ground pools have vinyl liners, so I'm not sure why one of the better cleaners would not work for my above ground pool ( That is 2.5' burried)? Any thoughts?