Guide to a Clean Pool: Water Distribution with Perimeter Supply Systems

May 1, 2017 | Categories: Pool Equipment & Systems

commercial pool water

The proper supply and distribution of clean, filtered water is a primary concern when designing the return system for a commercial swimming pool.  Even the very best filtration system is of little value if treated water is not properly distributed.

Read here to learn how to eliminate “dead spots” and have a clear and clean pool:

Dead Spots

Inlet return systems with too few inlets for return water, or systems with inlets incorrectly placed can cause “dead” spots where little treated water ever reaches.  These areas are identified by the deposition of fine dirt on the pool floor, the presence of algae on the poolside walls or floor, and a general lack of clarity in the pool.

Other indications of such “short-circuiting” include wide differences in residual chemical levels in various areas of the swimming pool.

Perimeter Supply Systems

Research has provided solid evidence of the benefits of continuous perimeter supply systems.

In these studies, it was concluded that continuous perimeter supply systems provided far superior water distribution than the widely spaced inlet system.

The continuous perimeter supply system concept has now been adopted in public and commercial pool construction throughout the United States.  In these systems, a continuous pre-engineered stainless steel fabricated water supply conduit circles the pool perimeter with strategically spaced supply inlets spaced no greater than 3 foot on center.

Inlet Location & Water Pressure

Supply orifices are located approximately 4 to 14 inches (100 to 355-mm) below the water surface and are directed downward at a 45° angle.

In the continuous perimeter supply system, hundreds of individual inlets supply smaller amounts of water (4 to 5-gpm GPM (.90 to 1.13-m³/hour) per inlet (plus or minus 10%) versus a few inlets supplying high volumes of water at high pressure.

The close spacing of the inlets around the perimeter ensures thorough mixing of return water with the contents of the pool.  This configuration eliminates the “dead” areas or areas of limited circulation.

[1]Functions and Parameters in Perimeter Overflow Systems for Swimming Pools, November 1975. National Sanitation Foundation, Ann Arbor, Michigan



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