Sizing a pool pump from turnover
<Assets TBC> A pool equipment pad with the pump and filter
Turnover is the time it takes for the whole pool to pass through the filter once. Many residential pools are designed to turn over in about eight hours.
Divide the gallons by the turnover time in minutes to get the flow. A 20,000 gallon pool turning over in 480 minutes needs about 42 gallons per minute.
The pump then has to deliver that flow against the resistance of the pipes, the filter and the heater, which depends on pipe size and length. That is why two pools of the same size can need different pumps. PoolTools will size the pump from the designed gallons and the plumbing run. It is in development.