Pool Filter Size Calculator

This calculator determines the optimal filter size based on your pool volume, desired turnover rate, and filter type.

Calculation Formula:

Flow Rate (GPM) = Pool Volume / (Turnover Hours x 60) / Filter Efficiency

Filter Types & Efficiency:

• • Sand Filter: 85% efficiency, lowest cost
• • Cartridge Filter: 90% efficiency, easy maintenance
• • DE Filter: 95% efficiency, finest filtration

Recommended Turnover Rates:

• • Residential pools: 6-8 hours
• • Commercial pools: 4-6 hours
• • Spas/Hot tubs: 15-30 minutes
• • Wading pools: 1-2 hours

Filter Sizing Guidelines:

• • Sand: Based on tank diameter and flow rate
• • Cartridge: ~2 sq ft filter area per GPM
• • DE: ~1.5 sq ft filter area per GPM

Important Considerations:

• • Oversizing improves performance and reduces maintenance
• • High bather loads require faster turnover rates
• • Environmental factors affect filter requirements
• • Pump capacity must match filter requirements
• • Local codes may specify minimum turnover rates

Maintenance Requirements:

• • Sand: Backwash weekly, replace sand every 5-7 years
• • Cartridge: Clean every 2-4 weeks, replace annually
• • DE: Backwash monthly, add fresh DE powder

Cost Considerations:

• • Sand filters: Lowest initial and operating costs
• • Cartridge filters: Medium cost, easy DIY maintenance
• • DE filters: Highest performance but most expensive