There are those who swim in lakes, rivers, ponds, the sea. There are those who swim in chemical swimming pools. (By chemical swimming pools, I mean the ones we usually see – lined with blue tiles and filled with water that smells of chlorine or some other sterilising chemical.) How many have come across a pool that is a cross between the two? A pool that has been created by the hand of man, in the same way as a garden pond, but which can be swum in? Not only because of its size, but because the water is clean enough to swim in, just as the sea, rivers and lakes are. These are Natural Swimming Pools, gaining popularity all over the world, mainly among private pool owners but also in the realm of public pools.
Why do people choose the natural pool over the chemical one? Here are some reasons in people's own words:
“It reminds me of my childhood.” (This usually comes from people over 40. Urban-raised youth rarely has memories of swimming in ponds and similar small bodies of water.)
“I am allergic to chlorine.”
“It's my water garden – a part of my garden in every season.”
“It's so ecological.”
“It makes me feel a part of nature, like walking in a forest or climbing a mountain.”
How does a natural pool function?
Think first of how a chemical pool functions. There is all the water. To make sure that the water stays clean, i.e., free of particles that could putrefy, there is a system of circulation so that the water can pass through filters. This 'cleaning', however, isn't enough. Bacteria cannot be eliminated by filtering – and if people have to enter the water and swim, they need water that is free of harmful bacteria. (Keeping in mind always that every person who enters releases substances into the water that could be harmful to other swimmers.) The solution, then, is to introduce a substance that effectively kills these pathogens and keeps on killing them. Chlorine.
Coming back to our original question: How does a natural pool function?
To begin with, you have to understand that a natural pool is made up of two specific areas – the swimming area and the regeneration area. The regeneration area is the part given over to the plants and the gravel (or clay) that the plants are rooted in – the part that gives the pool its natural look. And the swimming area is the part that is used by swimmers.
This tells us that the plants and the gravel are actively involved in the regeneration, or the purification, of the water. How? It's quite simple: putting together these natural elements creates an ecosystem. An ecosystem is when a set of (organic and inorganic) elements live together and are interdependent for their well-being (the well-being of the individual and the well-being of the species). These elements are: the water (of course), the gravel and the aquatic plants. Other contributors to the ecosystem, such as animals and bacteria, come uninvited and do not need to be put in. This ecosystem maintains itself with a little help from the hand of man. The help consists in the circulation and filtering of the water. Circulation is required so that the water can pass through filters, thus removing the larger debris (such as fallen leaves or dead animal matter). But this 'cleaning' does not mean that the water is pure and safe for bathing in. For this, the water has to pass through a biological filter, i.e., the gravel.
To sum up, this is how the water is kept clean:
plants use decomposed matter so that there is no waste buildup in the water
filters remove larger debris (that would also decompose naturally and be absorbed by the plants but over a longer period of time)
the water, as it circulates, passes through the gravel and is now pure in the same way as spring water is pure. The purification is done by the earth's own metabolic processes. In such a setting, there is no place for pathogens.
A natural balance comes into being, forming a living, dynamic, ecosystem. A human brings together the plants, the water and its circulation; Nature does the rest. Animals come along – water fleas, pond skaters, dragon flies and frogs find a home for themselves or their offspring; birds and bats fly in to feed off the insects or their larvae; everyone contributes to the upkeep of the 'house'. There are those pool-owners who introduce fish as well, making the family larger. And this can invite fish-eating birds... “The more, the merrier.”
That, in a nutshell, is a Natural Swimming Pool. Try one and you'll never want to enter a chemical pool again.