After multiple years of efforts and more than $30 million spent by governments and environmental groups to clear blue-green algae from Lake Tuggeranong, the unwanted growths are still blooming in large numbers on the body of water.

The most recent initiative to improve water quality in one of Canberra's biggest lakes involved the launch of floating wetlands, designed to absorb many of the nutrients that form the algal blooms.

The $270,000 installation, which is being trialled for two years in a Canberra first, is the latest in a long line of measures designed to clear the notorious blue-green algae from the lake.

Algae levels in Lake Tuggeranong have surged in recent years, driven by warmer weather, with the lake closed for extended periods of time as recently as this year.

Despite the millions spent by the ACT and federal governments as part of the Healthy Waterways project on initiatives to clear the blooms from the lake, University of Canberra researcher Fiona Dyer said there was no silver bullet for fighting algae.

"Clearing algae is like vacuuming a house. You don't do it once and assume you never have to do it again," Associate Professor Dyer said.

"If you want to keep nutrient levels low, you have to constantly work at it and it requires a significant number of people to get involved and it's also going to require a significant investment for that to continue."

Lake Tuggeranong was allocated $30.2 million in 2014 as part of the $93 million Healthy Waterways project.

The ACT government contributed more than $8 million to the entire project while the majority was funded by the Commonwealth.

That funding was spent on several initiatives such as the creation of seven rain gardens and ponds in various locations across the lake.

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Those rain gardens were set up to absorb nutrients like nitrogen and phosphorus that, if left to fester on the lake under the right conditions, would create blue-green algae.

ACT Healthy Waterways program manager Ralph Ogden said those measures were used to divert the nutrients away from stormwater drains.

"Another measure in the Tuggeranong catchment is a channel restoration, which is a cement channel and that got turned into a more naturalised channel which will trap sediments," he said.

"There's been a combination of modelling and feedback [to the initiatives] and we find out pretty quickly if they're not working."

An additional two research projects led by a team at the University of Canberra were also developed to find long-term solutions to the algal blooms.

One of them involved placing mesocosms, which look like big plastic tubes, into the lake to test various chemical solutions that could be used to treat the algae.

Associate Professor Dyer said urban catchment areas were prone to high levels of nutrients that caused algal blooms.

"The fundamental thing is to reduce the amount of nutrients that end up in the lake," she said.

"The main thing that needs to be done to reduce algal blooms is not a short-term fix and it's not something where you spend a chunk of money and it just goes away.

"In terms of ensuring you don't have algae in the lake, that's a much larger long-term investment."

Not all initiatives to help fix the lake's algal problems have been implemented, however, with one potential idea being to drain the lake entirely to find the source of the issue.

Another was to install air bubblers on the lake bed, which would have stirred the water up from underneath and made it less likely for the nutrients to ferment in hot weather and become algae.

Southern ACT Catchment Group chair and vice-president of the Tuggeranong Community Council Glenys Patulny has spent multiple years campaigning for the clean-up of Lake Tuggeranong and said good progress had been made.

"It is going to take a whole lot of time to stop it, though," she said.

"One thing that has been good with the floating wetlands is that has got people talking about the lake and we hope this will have an impact and make people more conscious of the work we're doing to help clear the lake."

While the floating wetlands may be the most recent measure to try and put a stop to blue-green algae, Mr Ogden said it would not be the last.

"Right now, we are in a big planning and rethink phase," he said.

"Once you have done a big investment you need to pause and see what is and isn't working."

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