What Size Pump for a 8,000-Gallon Pool
What size pump a 8,000-gallon pool needs: about 17 GPM for an 8-hour turnover (1,000 GPH). Buy a pump rated near 22 GPM for head loss.
For an 8-hour turnover on a 8,000-gallon pool, you need about
17 GPM
which is 1,000 gallons per hour through the filter
A 8,000-gallon pool needs to move about 17 gallons per minute to turn the water over once in 8 hours, which is 1,000 gallons per hour. The math is just your volume divided by the turnover hours, then divided by 60 to get GPM. One turnover in roughly 8 hours keeps the water clear, the chemistry mixed, and debris filtered without running the pump around the clock.
| Turnover target | Required flow |
|---|---|
| 8-hour turnover | 17 GPM (1,000 GPH) |
| 10-hour turnover | 13 GPM |
| Buy a pump rated about | 22 GPM (1.3x for head loss) |
The catch is head loss. The GPM above is your target flow, but real flow is reduced by pipes, fittings, the filter, the heater, and the height water is lifted, all of which add resistance called total dynamic head. A practical rule is to choose a pump rated about 1.3 times your target, so look for one that delivers near 22 GPM, then confirm it hits your real target on the manufacturer pump curve at your system head. Also make sure your filter is rated for at least this flow.
A variable-speed pump is almost always the smart pick for a 8,000-gallon pool. Instead of one loud, power-hungry speed, it runs longer hours at a lower, quieter speed to move the same daily volume, often cutting energy use by more than half. Many regions now require variable-speed pumps above a certain size. Set a schedule that hits your daily turnover at low speed, then bump to high only for vacuuming, heating, or running a spa or salt cell.
Pump & filter gear for this pool size
Runs longer at low speed, cuts energy use.
Match the filter to at least your pump flow.
Single or variable speed, sized to turnover.
Get the exact number for your water
The figures above are computed for a 8,000-gallon pool using standard formulas. To dose to your real test readings, open the Pump Size Calculator and enter your current and target levels. Not sure of your volume? Start with the pool volume calculator, then come back. You can also see every chemistry and equipment number for this size on the 8,000-gallon pool guide, browse all pool answers, or return to the PoolCareCalculator home page.
Frequently Asked Questions
How was the number for a 8,000-gallon pool calculated?
Every figure on this page comes from standard pool-care formulas applied to 8,000 US gallons, not a guess. Dosing scales with volume, so the same method works for any pool size. Always confirm against your own water test before adding anything, since real pools vary.
Is this dose exact for my 8,000-gallon pool?
Treat it as a close estimate. Product strengths, your starting readings, and your CYA all shift the real amount. Add a little less than the calculated figure, run the pump to circulate, wait, and retest before topping up. It is always easier to add more than to undo an overdose.
Can I mix pool chemicals to save time?
No. Never mix two pool chemicals, including two different chlorine products or chlorine and acid, since the reaction can release toxic gas or cause a fire. Add one product at a time, pour chemical into the water, run the pump, and retest before adding anything else.
Taking care of a pool?
Use our free calculators and guides to get every number right.
Pool Care Planner: $39