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  • Rockingham Pool & Spa Solutions

Cloudy Swimming Pool Water

Updated: Feb 18, 2021

Cloudy pool water is such a common issue, it’s one that every pool owner experiences. One minute you have your pool looking amazing, ‘it’s your crystal clear sparkling oasis’, the next it’s looking cloudy, hazy or milky.

Your First Thought is, so what happened to make my pool water turn cloudy, almost before my eyes!


Well the answer is, a large number of tiny particles of matter have been either introduced or fall out of solution into the water and now these particles reflect back light – which results in the appearance of cloudy swimming pool water.


Where do these particles come from, what causes them;

  1. Environmental - Algae, leaf mold, dust, bird droppings, flower pollen, water run off and fine sand.

  2. Mechanical - Inadequate circulation,dirty/damaged filtration equipment or insufficient filtration time.

  3. Chemical - The chemical balance of your pool water, chlorination, pH, calcium carbonate, calcium hypochlorite and alkalinity levels.

  4. Human - Sunscreen oils/lotions, skin proteins, body oils, perspiration and bodily fluids.

What you need to know about these particles – as this will help make sense of how to treat and get rid of them.

  1. They are from 0.5 to 5.0 microns so extremely small. Therefore they are too tiny to be easily caught by the pool’s filtration system.

  2. They carry a negative electrical charge. That means they repel each other and each particle hangs in isolated suspension in the pool water. Why do I need to know this? Because some of the treatment methods involve actually changing the particles’ electrical charge that way they stick together forming large enough coagulated particles that your pool filtration system can then deal with.

Next, is the varying degrees of cloudiness. This is often a clue as to the cause and helps determine the appropriate treatment.

  1. Dull or Flat – The pool water has lost its sparkle.

  2. Hazy – More than just appearing dull or flat, the water actually isn’t clear anymore.

  3. Cloudy – The water has a definite milky quality.

  4. Opaque – Very milky pool water that you can’t see the bottom.

So Why Is My Pool Cloudy? Just as there are any number of sources for the cloudy pool water, there are any number of reasons why these particles suddenly appear. Very often, there’s not so much a single reason, as there are a number of different reasons which combine together and feed off one another, giving you the end result that your pool water turned cloudy.

Also, if you’ve recently treated your pool for an algae infection, the water will be cloudy. That’s because what you’re now seeing is dead, white algae. To be sure, dead algae are a lot better than live algae, but your pool will be cloudy until you vacuum it away.

How to Fix a Cloudy Pool - accurate water testing is the first step in fixing a cloudy pool. Rockingham Pool and Spa Solution offer a free water testing service or you can book one of our certified technicians to come and sort this out for you. We strongly recommend professional testing if you have cloudy pool water .

Now for the Good News. In most cases, the fix for how to clear cloudy pool water is fairly simple. All that’s normally required is the administration of the correct dose of some products, a water clarifier and/or flocculants dependent on the pool water testing results.

Remember these two important things about the particles...

  1. They’re small, and

  2. They repel each other.

The way that clarifiers and flocculants work is that they neutralise the electric charge so that the particles bond together into something either big enough to be filtered, or else heavy enough to sink to the bottom of the pool for later vacuuming.

The important thing however when treating cloudy pool water, is DON’T USE TOO MUCH product to treat (overdose your pool water). Using too much won’t just neutralise the electrical charge, it will reverse it. Making your pool water worse. Rockingham Pool and Spa Solutions strongly recommend you contact us to get professional testing, advice on the diagnosis, treatment products and amount to administer.

2 Take Away Points.

  1. Remember that cloudy pool water can be caused by multiple factors.

    1. Check that one of these isn’t mechanical - make sure your filtration system is clean and operating efficiently.

  2. Make sure that your pool has consistent and sufficient chlorination.


The staff at Rockingham Pool and Spa Solutions are waiting to help you.


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