What is the filter rate for sand in gallons per minute per square foot (gpm/sq ft)?

The filter rate for sand in swimming pools is typically set at 12 gallons per minute per square foot (gpm/sq ft). This rate is widely accepted as the optimal flow for sand filters, ensuring effective filtration while preventing the sand from being disturbed too much, which could lead to inefficiencies in capturing dirt and debris. Operating within this standard flow rate allows for adequate contact time between the water and the filter media, leading to better water clarity and quality.

Understanding this figure is crucial for pool operators, as it aids in the proper sizing and operation of filtration systems, directly influencing pool maintenance practices and water quality.