Flow rate (GPM)
Also called: GPM, gallons per minute, flow.
Flow rate is how much water a pump actually delivers against your system's resistance, measured in gallons per minute (GPM). Pool equipment publishes its minimum flow as a GPM, never an RPM, because the pump speed that produces a given flow depends on your own plumbing.
Why it matters
Flow is how you size a pump and how you set its speed. The codes give a band: gallons ÷ 720 is the minimum GPM your equipment must be able to deliver, and gallons ÷ 360 is the most your filtering speed should move. Every device on the pad then sets a floor. Pentair's MasterTemp manual states a minimum 20 GPM, a salt cell's flow switch stops it generating below its own minimum, and Hayward HeatPro and Pentair UltraTemp heat pumps need 30 GPM. A filter sets the ceiling: a pump's flow should land under the filter's maximum. On an above-ground pool, size to pool gallons ÷ 480.
In numbers
On ENERGY STAR's identical test system, about 31 GPM takes 1,110 RPM on a Pentair IntelliFlo VSF and 1,634 RPM on a Pentair IntelliFlo 1.5 VSF, which is why an RPM from a chart does not transfer.