Every chemistry problem, cloudy pool, and equipment failure eventually traces back to flow. If water isn't moving at the right rate through the filter and chemical feeders, nothing else in the pool operates correctly. This pillar is the hydraulic foundation.
The turnover math
Turnover rate (hrs) = Pool volume (gal) ÷ (Flow rate gpm × 60)
Code-required turnovers by pool type (minimum):
- Residential pools: 6–8 hours
- Public/commercial pools: 6 hours
- Wading pools: 1–2 hours
- Spas: 30 minutes
- Splash pads: 30 minutes or less
Four turnovers filters approximately 98% of the water. More than that is diminishing returns. Fewer than that is a water-quality bomb waiting to detonate.
What operators actually need to know
- How to measure actual flow vs. designed flow
- Total dynamic head and pump curves
- How to spot and stop cavitation before it destroys an impeller
- VGB Act compliance and dual-drain configurations
- Surface-water removal and why skimmers/gutters do 80% of the cleaning
