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How does the water stay clean?

Clear, clean water is the naturally occurring state in ponds and lakes if the body of water is large and deep enough. Swimming ponds are purposely built to emulate this state and are a prime example of how we can harness nature's intelligence effectively. 

A conventional swimming pool uses chemicals to kill micro-organisms in the water such as phytoplankon (microscopic single-celled algae, which in abundance make the water go green) and bacteria. However this isn’t necessary in a natural pool where the cleaning work is carried out by micro-organisms which exist together in equilibrium. 

This is the basic principle of a swimming pond - to use the natural purifying properties of plants and micro-organisms to sustain clean, clear and healthy water.

So you don't have a filter then?

In natural water, the main filter is the whole water body, as each part of water is constantly being filtered by microscopic life-forms. 

However, in swimming ponds it is also essential to keep the nutrient levels very low, to ensure that single-celled algae is always controlled by zooplankton, and to prevent the growth of blanket weed (string algae). To do this we filter the water through shingle and other mediums using a small pump.  Plants also perform a useful function taking nutrients out of the water as they grow.  By keeping the levels of key nutrients low and in balance, algae is not able to grow and the result is clear, clean and healthy swimming water.

    We use standards required by the German swimming pond association (more stringent than the International swimming pond standards, which are adopted by default by the British Association of Natural Swimming Pools), which are used in hundreds of public swimming ponds in Germany and thousands of priviate swimming ponds.  
     Below is a very simplified drawing of how our filter system works - in reality there are many elements which go into making up an effective filtration system but this shows the basic principle:




















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Natural water cleaning
How much maintenance is needed?

A swimming pond needs much less maintenance than a conventional pool, as there are no chemicals to add and manage and the water does not need to be drained for cleaning and repairs

Nature itself carries out most of the cleaning service, but it is still a living and growing part of the garden and it needs looking after in a similar way.  The key to managing time spent on maintenance is ensuring the pond receives a small amount of regular attention. This amounts to emptying the skimmer and ensuring that any leaves which may have blown in do not build up in large quantities. 

    Removing leaves (and discouraging ducks from visiting the pond) helps to keep the water's nutrient levels low.  On this basis (i.e. no extreme nutrients enter the pond) we can guarantee the water to be completely clear all the time.

Many people like to spend time looking after their pond themselves. However we also have a dedicated maintenance team and offer a maintenance service which can be as often or infrequent as you need.  We generally recommend that our maintenance team visits at least once a year to check on the pond's development and its equipment.

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What happens in winter?

One advantage of a swimming pond over a conventional pool is that a pond looks beautiful all year round. The water is not emptied and in fact the more mature and established the water is in a swimming pond, the more stable it becomes.  Constantly alive and evolving, our ponds change with the seasons, maturing over the years and allowing the plants to grow into their habitat.

Pond in winter

Our filter systems have a "summer" and a "winter" switch - over winter the pump is off nearly all the time as the pond lies largely dormant, ready for the increase in temperatures in the spring.

In the autumn we cut back the plants to about 4-6 inches high.  This ensures organic matter doesn't fall back into the pond and decompose, so the nutrient level in the water stays low throughout the winter, ready for the spring.

Can you heat the water?

This is a common question in the northern US and the answer is yes, the water can be heated to 80 degrees F or in some special cases higher than that.  (For example we built a pool and heating system enabling the swimming water to be at 83 degrees F all year round, but this required a very specific design.) 

    However we generally recommend that people try their pool first, for one season, without heating. We can always install the necessary pipework during the construction stage and if required, connect it to a heating system at a later date.

People very often ask about heating when we first talk to them, but we almost always find that once they are swimming in the pond temperature is not the issue they thought it was beforehand. Particularly for natural designs, water in the shallow areas heats up quickly in the sun and can raise the natural temperature of the whole pond to 80 degrees in the summer.

    Perhaps more importantly, natural water feels much more comfortable on the skin and is not as "harsh" as chemical water. So what might feel cold in chlorinated water, 73 degrees F for example, actually feels comfortable in natural water. But the bottom line is yes - we can heat your swimming water, basically to whatever temperature you like.

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How much does a natural swimming pond or pool cost?

Costs can obviously vary and are dependent on size and other factors such as the number of features.

Natural designs are the easiest to estimate, because although the shape of each pond is unique the basic features tend to be similar. As long as you have stable soil (e.g. clay, chalk), and a small number of features (e.g. a wooden ladder and small decking, or steps and a jumping rock), total project costs typically range from $80k to $200K.

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