The Kambah backyard has been transformed from a harsh, hot area with a chlorine pool in the middle to a shady freshwater natural pond that is like an oasis.

Mrs Mansbridge stumbled across the idea to convert her backyard swimming pool to something that requires much less effort on the internet one night.

It wasn't just the thought that she'd barely have to clean it again, although that was a main driver, but Mrs Mansbridge was also keen to reduce her use of chemicals, and invite nature back into her backyard.

That was about two years ago, and Mrs Mansbridge and her family, including her daughter Lisa, couldn't be happier.

"It's the most wonderful thing I ever did," Mrs Mansbridge said.

Lisa, a swimming teacher, was in primary school when the pool was built in the early 1980s.

She was in it nearly every day. When she had children of her own, they also enjoyed a refreshing dip in the backyard pool. But when the children got older, they stopped using it as much. Mrs Mansbridge said it was around the time they got evaporative cooling installed inside, and the children could cool down in that instead.

Lisa said her mother still spent all her time balancing the pool, "making sure the chlorine is the right amount, and if you get the slightest bit of green, or cloudiness, adding more chemicals".

Mrs Mansbridge would clean it, balance it, put the solar cover on and off every day... It was all getting just a bit too much.

"Then I saw the Ku-ring-gai Shire website and I read it and I got hooked," Mrs Mansbridge said.

The website is titled "Pool to pond: create a haven for plants and wildlife" and is produced by a Sydney council for its ageing residents, who were having trouble maintaining their chlorine pools.

"This will be our second summer with it," Mrs Mansbridge said.

"Last year we thought it was fantastic and the bulrush was only half the height."

The process to convert the pool was one where Mrs Mansbridge was warned to "hold her nerve". It involves emptying the chlorinated water and letting the pool go green before adding in platforms for new plants and then gradually filling it.

"It looked terrible. It was green, it was horrible and you think you'll never get it right again."

When the pool was re-filled, Mrs Mansbridge added trout, but the first release died as there wasn't enough aeration.

Now, she has silver perch, trout and their food source of gudgeons stocked in the pool. She catches and eats the trout, but has recently learnt that silver perch are protected so she intends to let them flourish.

So far, she's caught five trout ranging from 400 to 700 grams each.

"It's not really like fishing, you can't throw out the line. You've just got to drag it around," she said.

Mrs Mansbridge said the new freshwater pool takes "hardly any work".

"It's easy gardening, and it's a pleasure in summer because you're hot and you go in, scoop up a bit of azolla and trim off a few dead things."

"It takes the hard work out of it, you're not putting chemicals in, the birds and the bees love it, they're always here, and it's just so relaxing," she said.

"You can sit out here in the morning with a cup of coffee or in the evening in the summer. I love the fish because you see them jumping and when the bugs come you see them leaping up for them. Even without the fish, it's just so relaxing."