Feature

Greening the backyard pool

G Magazine

Get the greenest backyard pool with this guide to saving water, energy and cutting down on chemicals.

in-the-swim

Natural pools use purifying systems that mimic those in nature, by using gravel and plants to clean the water.

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On a blazing summer’s day, there are few things more blissful than cooling off in your very own backyard swimming pool. But spare a thought for the impact your pool may have on the environment. There’s all that water needed for refilling and filtering, there’s the energy used in cleaning and heating, not to mention all the chemicals required to keep the water balanced. The good news is there’s a lot you can do to make your swimming pool more environmentally friendly, whether you’ve got an existing pool or are planning to build
a new one. Best of all, business is booming in ‘natural pools’ for Australian backyards, which are chemical-free, and rely instead on natural filtering systems such as gravel and aquatic plants to keep the water fresh.

ECO POOL ESSENTIALS

How do you minimise the impact that a traditional swimming pool has on the environment? The main areas to target are water wastage, energy that is used in cleaning and heating, and the chemicals that are used to keep the water clean.

Water wastage is a big worry with swimming pools, particularly when you consider the average domestic pool holds 22,000−60,000 L of water. Once filled, pools need topping up for backwashing, part of the filtration process, or because of evaporation. Pools can lose up to 5 mm a day through evaporation, but a pool cover or blanket will slow this down by up to 95 per cent, while also boosting the performance of your pool’s heating system if you have one.

“Also consider installing water-saving products such as rainwater tanks to top up the pool so that you’re not using mains water,” says Spiros Dassakis, of the Swimming Pool and Spa Association of NSW.

Older pools can get leaks in the membrane and piping, leading to further water loss of up to 7000 L of water a year. Make sure you check your pool regularly for any sign of cracks or leaks.

Chlorine is the main chemical used in pools to keep the water free of harmful bacteria, but it can cause problems for people with respiratory conditions like asthma, and irritate eyes, noses and skin. It can also cause environmental effects if any water from the pool is drained elsewhere. “A salt chlorinator will drastically minimise the need for chlorine, as it produces chlorine from the pool water [and a store of salt] on site,” says Bryan Goh, of pool equipment supplier Waterco.

It also pays to keep a check on the water quality and chemistry in your pool, with regular DIY or tests from
a pool expert. “Keeping your pool water in balance and healthy requires less chemical usage than trying to turn a green pool back to blue,” says Goh.

If you’re building a new pool, shop around for pool equipment that’s the most water- and energy-efficient. “It’s important to weigh up the long-term running cost of cheaper, inefficient technologies,” says Dassakis.

“A quiet, efficient pool pump combined with an efficient filter and piping system is likely to be the best option. Some of the new multi-speed and variable pumps can save you up to 70 per cent in energy costs.” Meanwhile, sand filters need backwashing to be cleaned, using up to 8000 L of water a year, while cartridge filters don’t require it.

Think of natural design options to maximise environmental performance of your pool. “The local climate, wind and humidity have a strong impact on the environmental performance of a swimming pool or spa,” says Dassakis. Position your pool carefully to maximise sunshine and natural heating but protect from drying winds. Avoid placing a pool near trees that drop lots of leaves, but consider planting hardy evergreen trees as a windbreak in windy areas.

Pool heating extends the time you use the pool but can be a big energy guzzler. The most efficient heating option is solar, followed by heat pump and then gas. “A heat pump extracts heat from the air, intensifies it and transfers it to the pool water,” says Goh. “It relies on the existing filtration pump and doesn’t require additional pumps. The gas heater is the least energy efficient, but will deliver heat quicker, and is the more costly to run.”

In terms of materials, if you’re putting in a new pool, concrete is a more eco-friendly option for construction than fibre-reinforced plastic. “Concrete acts as an insulating jacket which can reduce heating costs and it’s a sustainable material, as it can be dug up, crushed and recycled for other purposes,” says Neil Davey, of FMG Engineering.

ABOUT ALL-NATURAL POOLS

They’ve been big in Europe for almost 30 years and now natural pools are gaining popularity in Australia. They use water purifying systems that mimic those in nature, in freshwater lakes and waterholes, filtering water over a natural material such as gravel and plants to clean the water.

“It’s a chemical-free environment, with no salt or chlorine in the water,” says natural pool expert and landscape designer Phillip Johnson. “And they don’t use as much energy as conventional pools.”

The natural pool system pumps water out of the swimming environment, through a separate filtration zone. “The water passes through a material, such as gravel, and the water is cleaned as it moves through,” says Johnson. “I like to plant aquatic plants to absorb some extra nutrients from the water and bring a sustainable emphasis to the pool.”

Natural pools can be designed from scratch to suit any architectural style, whether it’s the more authentic, wilderness waterhole look, or a more modern or traditional backyard pool design. “We recently designed one for a French provincial style house with a more formal pool,” says Johnson.

Best of all, the chemical-free filtering system used in natural pools can be retro-fitted to existing, traditional swimming pools. “A third of our work is converting conventional pools into natural pools,” Johnson says.

ECO POOL KNOW-HOW

POOL COVERS or blankets will slow water evaporation and cut pool heating costs by up to 50 per cent.
SOLAR heating is the most efficient way to heat your pool, followed by heat pumps, then gas systems.
POSITION your pool with the local climate in mind. Consider sun and wind exposure.
SHADECLOTHS over pools will help slow evaporation, especially in hotter, northern states.
LED lights or carbon-fluorescent lights are good energy-efficient light options for pool areas.
CARTRIDGE FILTERS use less water than sand filters because they don’t need backwashing.
SALT chlorinated pools use fewer chemicals than regular chlorine systems.