Avoiding dead zones
There are two ways to make sure a swimming pool is designed and circulated to eliminate ‘dead zones’—especially with today’s intricate pool designs and elaborate features, as mentioned previously.
First, make sure the plumbing is properly balanced. One of the most important parts of a well-balanced circulated pool is having a hydraulically sound plumbing layout throughout the suction and return sides of the system. Taking larger pipe sizes and then breaking them down to smaller sizes in balanced method around the pool will ensure the entire volume of water in the pool is properly circulated, eliminating any ‘dead spots.’
Secondly, ensure the return lines are placed properly and in the right direction. When bringing water back to the pool after it passes through the filtration system, it is important to make sure the entire volume of water is returned to the pool and distributed as evenly as possible. This is where the importance of balanced plumbing around the pool and properly located returns come into play. If executed properly, it will help to make sure all areas of the pool are circulating water.
A technique used by many contractors today is installing the return lines parallel to each other—throughout the installation—which allows water to return to the pool in a circular motion. By using this hydraulics technique, as the water completely circulates around the pool it also passes by the skimmers in a strategic fashion that aides in cleaning the surface, as well as distributing the water.
One suggestion is to cap the end of the return line to increase the hydraulic performance of the lines that are furthest away in the plumbing schematic. This will ensure proper water circulation throughout the entire pool.
In larger pools, it often makes sense to divide the plumbing and pumps into three sections, each with its own pump system. This way, each section of the pool has its own ‘zone’ with a dedicated circulation system. For example, a 6.1- x 12.2-m (20- x 40-ft) pool that includes a grotto with cascading waterfall, a slide (with its own water system) in the deep end, a sundeck with fountain and cuddle cove, and a play area (reverse radius section) in the shallow end, should be divided into three zones.
Starting in the shallow end, the first 3 m (10 ft) should be considered zone one, while the mid-section of the pool (4.5 m [15 ft] plus) should be divided into the second zone. Finally, the deep end area, or last 4.5 m (15 ft), should be considered the third zone. Pumps and plumbing should be sized accordingly for each zone.
Creating zones allows for better circulation in the pool which helps with better surface cleaning as well as better chemical dispersion if the pool is equipped with an automatic feeder. If the pool is not equipped with the proper size circulation pump, the pool water will not turn over the proper number of times to properly sanitize and clean the pool.
| What is a ‘dead zone’? |
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| In pools, dead zones comprise of areas such as corners where the circulating motion of the water does not reach. These areas can be created by improper balancing of the return system plumbing or improper pump size.If the pump or plumbing is undersized for the given body of water, there will not be enough flow throughout the entire pool. As a result, all areas will not get proper circulation, filtration, or chemical delivery (if chemicals are returned to the pool in the return system). Any pockets that lack sanitized water can lead to algae growth or other issues that could affect the pool. |
