How Do I... Bring My Dark, Cloudy Pool Back to Blue?


How Do I... Bring My Dark, Cloudy Pool Back to Blue?

Swimming season is almost here – if your pool is looking less than sparkling, here are the steps you need to take.

Rick Graham, pool and spa expert at Swimart, shares the secrets to bringing your dark swimming pool back to a bright, sparkling blue.


There are many reasons a swimming pool goes dark or cloudy, but the most common ones include:

  • A chemical imbalance.
  • Not enough sanitiser in the water.
  • Algae blooms.
  • Inefficient water circulation.
  • Faulty filtration equipment.

Can weather extremes make it worse?

Definitely, which is why it’s so important to have a pool cover to protect your pool water from the weather.

Here’s what weather exposure can do:

  • Hot weather causes evaporation, which leads to water imbalance and chemical loss.
  • Storms blow in debris and contaminants that lead to algal growth.
  • Heavy rain dilutes pool chemicals and causes water imbalance.


What are some signs that my pool water is unhealthy?

  • Cloudy water. This is caused by blooms of algae that result from a lack of sanitiser in the water.
  • When algae growth is out of control, pool water will turn green or dark brown, depending on the type of algae. You’ll see this first in places where the water circulation is poor, such as corners, steps and where the pool floor meets the walls.


Is dark or cloudy water bad for my health?

Yes. It can cause a range of health issues, including eye and ear infections, itchy skin and intestinal infections. However, it is important to note that you can have crystal clear water that is unhygienic too.



What should I do if my pool goes cloudy?

  • First, take a water sample from elbow depth to your pool specialist so they can recommend the correct chemicals and the right dosages to treat the algae.
  • Treating a pool with an algae bloom is fairly straightforward – add acid, chlorine and a flocking agent (with the amounts recommended by your pool specialist), then vacuum.
  • If the water is contaminated and requires bleaching, seek advice from your pool specialist. This is important because you’ll be handling dangerous chemicals and you need to understand how to use them safely – in particular, what not to do, such as pouring chemicals in the wrong order or putting acid in a container that once stored chlorine.



My pool water is dark green – should I just empty it out?

Don’t! No matter how bad it looks, never empty the water from your pool as it can create a number of financial and structural problems. This is because water acts as a stabiliser that weighs the pool down when it’s in the ground. When you take that water out, it can ‘pop’ out of the ground or the walls can cave in.


How can I prevent water from going dark or cloudy?

1. Check your pool’s chlorine and pH level every two days. This is especially important after a period of heavy usage, a very hot day or a period of solid rain.

2. Clean out your skimmer basket and the hair and lint pot in your filtration pump weekly.

3. To keep pool water properly balanced, take a sample from elbow depth to your local pool store for professional testing every week or so.

4. Use a quality algaecide to keep algae at bay.

5. Run the filter six to eight hours a day.

6. Regularly check sanitiser levels – ideally daily.

7. Check total alkalinity (TA) weekly with a test kit or by taking a sample to your local pool store.

8. Thoroughly backwash your sand or DE filter, or remove and clean the cartridge from your cartridge filter with a hose.

9. Keep the water level at least half way up the skimmer box opening.

10. Regularly brush or vacuum the pool walls and floor.



Source: Georgia Madden, Senior Writer, Houzz Australia, Houzz