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How It Works
The turnover rate tells you how long it takes for your entire pool volume to cycle through the pump and filter. Faster turnover means cleaner water. The Langelier Saturation Index (LSI) checks whether your water chemistry is balanced -- negative values indicate corrosive water that attacks metal and plaster, while positive values signal scale formation.
Most health codes require turnover times of 6–8 hours for residential pools and 4–6 hours for commercial pools. An ideal LSI falls between −0.3 and +0.3.
Example Problem
A 20,000-gallon pool has a pump that flows at 50 gpm. What is the turnover time?
- T = V / (Q × 60) = 20,000 / (50 × 60)
- T = 20,000 / 3,000 = 6.67 hours
This meets the typical 8-hour residential requirement with room to spare.
Frequently Asked Questions
What is a good pool turnover rate?
Residential pools should turn over every 6–8 hours, while public and commercial pools typically require 4–6 hours. Spa and therapy pools may need turnover as fast as 30 minutes.
What does the Langelier Saturation Index tell you?
An LSI near zero means balanced water. A negative value (e.g., −0.5) means the water is aggressive and will corrode metal surfaces and dissolve plaster. A positive value (e.g., +0.5) means the water tends to form calcium carbonate scale.
How do I size a pool pump for my pool volume?
Divide your pool volume by the target turnover time (in minutes): Q = V / (T × 60). For a 15,000-gallon pool with an 8-hour target, you need at least 15,000 / 480 = 31.25 gpm.
Related Calculators
- Microorganism Disinfection Calculator -- determine the CT value for pool chlorination.
- Rainwater Collection Calculator -- estimate water volume for topping off pools.
- Threshold Odor Number Calculator -- assess water quality complaints related to chloramines.
- Geometric Formulas Calculator -- calculate pool volume from rectangular or cylindrical shapes.
- Volume Unit Converter -- convert pool water volume between gallons, liters, and cubic feet.