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How to Know How Many Hours to Run a Pool Filter

Swimming pool water clarity is a combination of filtration and maintaining the chemical balance of your pool - Both are needed. This article will help you understand your filtration needs and how long the filter should be run.


1. Check with your pool supplier for proper testing kits and chemicals.

2. Use a pH and chlorine tester to see how much chlorine is in the water if the pool has an automatic feeder.

3. See how clean your pool is by examining the water, amount of bugs, etc.. on the water and in the water.

4. Running of the filter also depends on the size pool to filter ratio. If you have a small filter you may need to run it more. Depends on how many gallons the filter can process in a given time.

5. You want to run your filter daily so that all the water in the pool is run through the filter at least once. To accomplish this you need to factor how much water is in your pool and the size of your filter. Note that most pools are sized with filters that turn the water over in 8-10hrs.

Turnover Rate Calculation

1. Calculate the volume of your pool by multiplying the length x width x average depth in feet

2. Multiply this number by a standard multiplier which is 7.5 for rectangular and square pools and 5.9 for other shapes. Example 16x32x5x7.5= 19,200. This would give the volume of the pool in gallons for this 16x32 pool that has an average depth of 5 feet.

3. Calculate the flow rate of the pump and the resistance to flow in your plumbing system. The pump manufacturer can tell you the flow rate for certain resistances. You can estimate your pool plumbing resistance to be 20ft/lbs for small pools and 40ft/lbs for large pools or installations where the pool pump is far removed from the pool area. Also waterfalls and elevated solar systems will cause the ft/lbs resistance in the line to increase.

4. An average 1 HP pump might move 50 gallons per minute. This would be 3000 gallons per hour. The minimum recommended turnover rate for your pool is two complete turnovers in any 24 hour period. In this equation the pool would turn over completely in 6.4 hours meaning that for safe filtration the pump would need to run for 12.8 hours out of every 24 hours.

5. Run your pool pump at night for cooler operation of your pump

6. Add your chemicals at night when the sun is not depleting the chlorine in your pool

Source: wikiHow

Written by wikiHow on 2012/08/23

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