Swimming pool enclosures help to keep the pool clean over the winter closedown period. If you can prevent dirt and debris, such as leaves entering the pool it makes it much easier to open the pool in the Spring.
A pool that has been properly maintained is much easier and cheaper to get going again. There are a number of swimming pools enclosures, each suitable for different situations and budgets.
Mesh covers are a much better alternative. This is stretched over the top of the pool. It is held in place by stainless steel fittings which are drilled into the pool surround and attached to the cover with straps. These fixings make for a much more secure enclosure.
The mesh effectively acts in a similar way to a filter. The water is allowed through, but the dirt remains on the top. The mesh cover can be tailored to fit different pool shapes.
The spacings between the straps will depend on the size and shape of the cover. Generally the larger and more complex the shape of the cover then the more straps it requires. They are more expensive, per square foot. The manufacturer needs to know the exact pool size in order to allow for a good overlap.