Are you looking for a swimming pool which is 100% chemical free with clean, clear water for relatively wildlife free swimming? Do you want a flexible design with the ability to heat the pool? Then a natural swimming pool could be just the thing for you.
Natural pools use biofiltration systems to purify the water. This is done by carefully selected plants. The resulting water quality is similar to that of natural systems such as lakes. Natural pools do not contain irritating chemicals that can affect the eyes, lungs and skin.
Water purification is achieved by plants and earth, which serve to oxygenate the water and eliminate nutrients that could help unwanted algae and microorganisms to grow and which cause mosquito larvae to spread for example.
Natural pools have a similar balance of bacteria as that found in nature and are not sterile as is the case with chlorinated pools. They require minimal maintenance and the principle task is to fill them up when the water level gets low due to natural evaporation.
Most of these pools feature two connected areas. A lower one which serves as the swimming pool and a higher shallower pool which holds plants. This should contain aquatic plants, such as cattails, water lilies and duckweeds, which serve to remove bacteria and other contaminants.
Natural pools use biological filters to create clear, clean, and chemical-free water. These can be either gravel or plant filters. The water is passed through the filter by means of a pump depending on preference and climate. In Spain and Portugal, gravel filters would normally be considered more appropriate, since these are better suited to warmer climates.
Maintenance of natural pools is uncomplicated. Once a month all sediment should be removed using a specialist swimming pool vacuum cleaner. It is not necessary to empty natural pools in winter. If they do freeze over you simply have to wait until they thaw. Since the water pipes are located underground they should not freeze up.
Check out Clear Water Revival if you want some advise on design and particularly if you want to make a DIY pool. You'll see they don't agree with everything we have written above with regards to filters, but then they were not thinking about hot climes such as Southern Spain or Portugal.
Stan Dickens (FRICS) is a UK qualified Chartered Surveyor who has practiced in Spain and Portugal since 1989.