For massive 27,000-gallon above ground systems, we recommend a 'Pro-Grade' setup using the Black+Decker 3.0 HP Variable Speed pump. This provides the 56 GPM flow rate required to keep this large volume of water clear. Paired with the 1800 Series Filter, this system handles heavy bather loads and large debris with ease. By using a more powerful pump at lower speeds, you get whisper-quiet operation and superior filtration compared to standard above ground equipment.