Natural pools mimic nature so you can swim in soft, clear, chemical-free water

Remember the days when we could jump into a clean river, creek or little billabong to cool off on those steamy summer days? It may seem a while ago since we had water in our environment that was clean and safe enough to take a dip in, but you can create a natural swimming pool with clean safe, chemical-free water right in your own backyard.

Natural pools are taking the pool industry by storm, increasing in popularity with each passing year. Some natural pools are surrounded by rocks and plants that emulate the intrinsic beauty of a bushland waterhole; others are of contemporary design, signalling their natural status with a “floating garden” of aquatic plants that hug the edge yet don’t interrupt the sleek lines of the pool.

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What is a natural pool?

A natural pool can look like a waterhole you’d discover in hidden spots on a bushwalk or it can be a stylish traditional type of pool. “A natural pool is a body of water that does not use chemicals or materials (that is, salt or chlorine) to maintain cleanliness but instead uses a natural filtration zone to clean the water,” explains Phil Johnson of Phillip Johnson Landscapes, winner of multiple awards for eco-friendly design.

Phil explains that natural pools can be used for swimming, irrigation and bushfire fighting, which is what he does on his own property. While he specialises in the creation of billabong-style natural pools, a natural pool can be constructed using conventional materials such as tiles, fibreglass, exposed aggregate, pebblecrete or concrete, depending on your design. Or you could convert an existing in-ground pool.

Healthy oxygenated water and no stagnant water means mozzies are not a problem and insects such as dragon flies and boat men as well as water snails live happily in the plant life, making an enormous contribution towards cleaning the eco-system.

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Water collection

Swimming is a fun summer activity and a great form of exercise but pools require an enormous amount of water. It takes about 50,000 litres to fill the average backyard swimming pool. And, of course, water splashes out and evaporates, resulting in the need for regular top-ups. It’s estimated that a home with a pool uses 10 per cent more water each year than one without a pool.

Natural pools take water-wise principles seriously. When owning a pool, it’s water-efficient to capture rainwater on-site. You can install tanks that harvest rainwater from your house, garage or shed roofs, allowing you to fill and top up the pool without the cost or overuse of mains water.

With natural pools, Phil says, “The collected rainwater can be transported, either from tanks or straight from downpipes, into the body of water. The water first passes through a filtration zone, which cleans any nutrients it has collected, and then passes through into the pool. The water is then pumped from the bottom of the natural pool back into the filtration zone, cycling through the system again. “Because it doesn’t use chemicals to clean the water, it develops its own eco-system, which performs water cleansing and purifying.”

As in nature, the pool’s water will change. Phil adds, “It’s important to remember that the system is built to fluctuate with seasonal weather patterns, so it won’t always need to be topped up for it to be working and looking beautiful.”

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Filtration zone

Natural filtration is at the heart of a natural pool’s design. The filtration zone, which destroys bacteria and algae, can be referred to as a natural filter or bio-filter. Natural filtration is a system filled with native aquatic plants and zeolites (a natural mineral) that purify the water, whereas a bio-filtration system has biological and phosphorous filters instead of water plants.

The water from both filtration systems is clean and safe, allowing the water to develop its own eco-system that cleans and purifies. No chemicals at all are used in the process of either filtration system, which is of course the point.

Natural filtration

The filtration zone of a natural filtration system is a body of water planted out with aquatic plants (macrophytes) and zeolite which friendly bacteria attach to, acting as natural biological cleansers. They assist in absorbing nutrients out of the water. Phil says rushes such as Baumea sp., Juncus spp., Eleocharis sp. or the vigorous Ficinia sp. are ideal for this purpose, but the choice of plants really depends on your location. A skimmer box sucks leaves and debris from the water’s surface. The water is clean and safe and develops its own eco-system that cleans and purifies.

Bio filtration

A bio-filtrated pool looks like a chemically treated pool but operates like a natural pool. The only difference is that biological and phosphorous filters replace the water-plant component needed in the natural filtration system. The biological filter method is the same system as used in drinking-water treatment.

Peter Glass of Peter Glass & Associates, Australia’s longest-established natural pool exponent, says the construction of a bio-filtration pool is much the same as the construction of a conventional pool. He says, “Bio-filtration is an exciting system that uses a specially designed two-way pump system combined with an aggregate filtration zone to create an optimum environment for good micro-organisms to flourish. These in turn feed off any organic matter or undesirable bacteria in the water.”

The filtration bed can also be the location of aquatic plants but they are not essential to the bio-filtration system’s operation. “Aquatic plants assist in stabilising and visually enhancing the surface of the filtration bed and they also provide a wonderful interaction with nature,” says Peter.

He says the style of a bio-filtration zone can vary from a simple gravel filtration bed, with or without plants, that can be out of sight under a decking, to a veritable “water jungle” that boasts reeds, alocasias, papyrus and water lily species. The most exciting aspects of a bio-filtration system are that it eliminates the need for pool chemicals and has the potential to suit most pool designs and situations.

According to Peter, “We can still design magnificent swimming pools that can range from a sleek, modern style to a virtual billabong complete with water that is not only deemed drinking quality but also suitable for keeping fish.”

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The benefits

Ralf Schmiel of gartenART Natural Swimming Pools, a German designer who designed and built natural pools in Europe before moving to Australia, says, “We live in a time of re-orientation in the way we treat our health and our environment. We have begun to watch how we can reduce pollution and waste in our environment. Natural pools play an important role, as soft, natural, clear water is one of the most pleasant and healthy things for all creatures, including humans.”

Ralf adds that natural pools are significant because the water is clean, soft and safe to swim in. He says swimming in natural water can provide real health benefits, especially for people with allergies, asthma or skin problems. “Natural pools also mean the end of dried-out, bleached skin and hair and the sheer joy of swimming in natural water is a health benefit, too.”

Traditional pools use chemicals to keep the water free of algae and other impurities. Chlorine is used in most pools and more and more people, especially children, have developed allergies and eye irritation from some of these chemicals. Ralf says, “Imagine swimming in a pool with the water quality of a mountain stream: no chemical additives, just the simple elegance of pure water and fun.”

It’s good news on the environmental front, too, as no pollutants will enter the surrounding soil or groundwater.

Heating

If you were wondering whether you can heat a natural pool, the answer is yes, and the most sustainable way is with a pool blanket or a solar array on your roof. To protect the integrity of the natural pool and its ecology, heating must be gradual and not instantaneous. Also, temperatures should not exceed 28ºC.

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Natural care

As Phil says, natural pools form their own eco-systems, which maintain water integrity and health from the outset. But there are a couple of things you may need to do from time to time.

The filtration zone requires back-washing if it hasn’t been used for a while. If filling with water or topping up the water level from rainwater tanks, make sure the water tank has a good strainer basket and filter attached to eliminate debris or dirt that could be in your water tank. This will ensure the cleanest and freshest water possible in your natural pool.

Natural pools are seasonal, so it’s a good idea to check the aquatic plants a few times a year. You may need to replace some or add new recommended species.

Greening up

There are some measures you can take to convert your existing in-ground or above-ground pool, even if you don’t go the full way to a natural pool.

Less power

Swimming pools can be very greedy power consumers. For example, according to the NSW government, running an electric pool pump will increase your household energy use by 17 per cent and much more if you include pool heating. To address power usage concerns, a solar-powered pool pump should be installed. This will run your filter system and is suited to all water circulation applications, including swimming pools, which means all parts used are perfectly compatible with natural water or even chlorinated or salt water.

Solar pool pumps can achieve an exceptional overall efficiency of 92 per cent, which means less wasted energy and lower power bills. To heat your pool for extended swimming, you can install solar pool heating panels (they even come in kit form) on your roof or a cheaper yet effective option is to buy a solar blanket. The blanket has a double benefit as it will keep out leaves and debris which will, in turn, mean less power is consumed filtering and cleaning.

Pool lighting

If you want to ensure your pool consumes as little energy as possible, use LED lights. They are energy-efficient, have a long life, come in a range of colours and can lead to cost savings. High-quality LED lights often have a lifespan of more than 20,000 hours, with some up to 75,000 hours. This means they have to be replaced less often. Even ultra-bright LED pool lights consume less than 5 per cent of the energy used by conventional halogen lights so are an eco-friendly alternative.

Pool tips

• A water tank may be installed to capture rainfall from your roofs. The harvested rainwater can be used to top up your pool as required.
• Check that your swimming pool doesn’t have any cracks, damage or leaks that would result in water loss.
• Cover your pool with a good-quality pool cover. This will save about 90 per cent of water loss through evaporation. The cover will also keep out leaves and debris.
• If you want warmer water, invest in solar pool-heating panels (they come in kit form) or buy a solar blanket such as the Elite Solar Bubble from Elite Pool Covers, which will extend your swimming time by up to three months a year.
• Consider converting your existing pool into a natural pool by contacting a natural pool specialist.