Can anyone give me advise on a really great automatic pool cleaner for and above ground pool would be? I have had the Centennial Pool Blaster which ran without a hose and with a rechargeable battery. It quit working within 3 months. Now I have the Pentair Kreepy Krauly Shark and he keeps knocking over. I've been eyeballing the robotic ones and I know they are pricey but I am sick of rebuying vacuums. Any recommendations? Thanks!