What is the maximum flow rate through a sand filter typically recommended in gpm per square foot?

The maximum flow rate through a sand filter that is commonly recommended is in the range of 2 to 4 gallons per minute per square foot. This range is significant because it ensures that the filter operates efficiently, allowing adequate time for the water to pass through the sand media, which is essential for effective removal of suspended solids, bacteria, and other contaminants.

Exceeding this flow rate can lead to a reduction in the filter's effectiveness, as the water may move too quickly through the media, preventing thorough filtration. Additionally, maintaining this flow rate helps in minimizing issues such as channeling, where water may take preferential paths through the sand instead of evenly distributing across the filter bed. Hence, a flow rate within this range is crucial for achieving optimal performance and longevity of the sand filter system.