Pool Turnover Rate Calculator
Calculate how long it takes to filter your entire pool volume or find the required flow rate.
Calculated Metrics:
Understanding Pool Turnover Rate
The turnover rate is a critical metric in pool maintenance that measures the time required for the entire volume of water in your pool to pass through the filtration system exactly once. Maintaining a proper turnover rate ensures that your sanitizer is evenly distributed and that debris and contaminants are efficiently removed.
The Importance of Water Circulation
Stagnant water is the enemy of a clean swimming pool. Without adequate turnover, "dead spots" can occur where algae bloom regardless of chemical levels. Most residential standards recommend at least one complete turnover every 8 hours, while commercial pools often require a turnover every 6 hours due to higher bather loads.
The Math Behind the Calculation
To calculate your turnover rate manually, you need two primary numbers: the total volume of your pool in gallons and the flow rate of your pump system (usually measured in Gallons Per Minute, or GPM).
Formula for Turnover Time (Hours):
Turnover Time = Pool Volume / (Flow Rate × 60)
Example Calculation:
If you have a 20,000-gallon pool and your pump's flow meter reads 45 GPM:
1. 45 GPM × 60 minutes = 2,700 Gallons Per Hour (GPH).
2. 20,000 Gallons / 2,700 GPH = 7.4 Hours.
Determining Your Required Flow Rate
If you are trying to select a new pump or adjust a variable speed pump, you need to work backward from your desired turnover time. If your local health code requires a 6-hour turnover for a 15,000-gallon pool, you would calculate:
Required GPM = Pool Volume / (Target Hours × 60)
In this case: 15,000 / (6 × 60) = 41.6 GPM. You would need a pump and filter setup capable of maintaining at least 42 GPM.
Factors That Affect Turnover
- Filter Pressure: As your filter gets dirty, the PSI increases and the flow rate (GPM) decreases, slowing down your turnover rate.
- Pipe Diameter: Smaller pipes (1.5 inch vs 2 inch) create more friction loss, reducing the efficiency of the pump.
- Pump Speed: Variable speed pumps allow you to lower the GPM to save energy, but you must ensure the pump runs long enough to achieve at least one full turnover daily.