Cloudy Pool Water – Why You Have it, and How to Get Rid of it


Cloudy water in your pools; what are the causes of this unsightly problem or why do I have it in my pool? There are many known factors or reasons for cloudiness in your swimming pool or spa. The fact of the matter is that; there is no single cause for this swimming pool water problem. When we go to a water facility, we want to enjoy a clear, sparkling pool or spa.

However a swimming pool or spa looses its beauty, when the water is cloudy. This is very uninviting to swimmers like you and I; simply because of the dull, hazy, and cloudy water look of the pool.

Causes of cloudy water in pools and spas

The most common causes of cloudiness in swimming pools and spas include:

  • Improper or poor water filtration. Pool filters not functioning to their full capacity.
  • Insufficient or poor water circulation. In other words, poor water flow and turn over rate.
  • Poor pool water chemistry. Your pool chemicals are not properly balanced.
  • The early stages of algae growth which is caused by poor sanitation and oxidation levels, is also a swimming pool water problem; which leads to cloudy water in your facility.

Why is my pool water cloudy?

Cloudy pool water is a very wide open ended issue that many pool/spa operators experience worldwide. Still it has to be addressed if we are going to avoid green, milky, and hazy looking pool water. The cloudiness that we experienced in our pools and spas, is the results of the presence of small or fine suspended particles that are in the water. I know you may be asking the question “why don’t my pool filters filter out these particles?”

Well, the truth of the matter is that these particles are so minuscule that they cannot be filtered. This means that they pass right through our pool filters and right back out to the pool/spa. Because these particle are too small to be filtered, they are also very difficult to be removed from our swimming pool water by oxidation.

Causes of cloudy water in swimming pools


As I stated above, the cloudiness in swimming pools and spas is caused by the presence of fine suspended particles in the water, which are too small to be filtered out. One major set back with this swimming pool water problem, is that environmental factors such as the wind, rain, and the surrounding vegetation, are contributing elements that are responsible for these small particles in our pools.

We’re unable to control the environment, but there are other contributing factors that cause pool cloudiness that we CAN control. The other causes of cloudy water swimming pools and spas are:

  • Algae growth (green pool water) – This water problem is caused by low or inadequate pool sanitation/oxidation.
  • Poor pool water filtration – This is the results of a pool filter system being too small for the job or a system that is not functioning properly.
  • Insufficient time for filter turn over rate to be achieved.
  • Backwashing too frequently – It is very important that we allow our pool filters sufficient time to collect or filter out the water. Filters work better when they get dirty; however, we don’t want them to get too dirty; because our pressures on the filters will increase and our water flow will be reduced.
  • Poor pool water circulation – This is usually the results of a swimming pool pump being too small or not working at all.
  • Heavy bather or swimmers loads – This problem depletes your pool sanitation or disinfectant capabilities; thus, contaminating your pool water with residues of human skin, bacteria, suntan lotion, and cosmetics.
  • Pool heaters – If the heating system/s for your swimming pools and spas are inadequately treated chemically, you will have a build-up of bio-films and algae; which will lead to cloudy water eventually.
  • Bio-films build-up in your pool filters – Other than your pool filters, you can also have a build-up of bio-films in your swimming pool pumps and plumbing lines.
  • Insufficient sunlight in your pool or spa – Fact of the matter is that, we need the UV rays because they are a great source of natural oxidizers.
  • The pH of you pool water is too high – This causes your pool chlorine to work more slowly or not at all. Therefore cloudy pool water is the result of algae growth.
  • The alkalinity level of your pool water is too high.
  • The stabilizer (cyanuric acid) level in your pool or spa is too high.
  • Your pool chlorine level is too low.
  • The calcium hardness level of your swimming pool water is too high.
  • Your TDS (Total Dissolved Solids) level is too high.
  • You have high levels of metals in you water. This gives you a discolored pool water appearance.

How to clear up cloudy water in your swimming pool

Usually the first step in correcting a cloudy water situation, is by checking your swimming pool filtration system. You need to clean your pool filters as needed and re-establish proper water flow rates. There are certain products that are available which can aid in cleaning your filtration system.

These cleaning agents are designed specifically for cleaning different types of filter media. So once you know the type of filter media your pool/spa filter carries, you can purchase the correct filter cleaning aid. Now, once you have cleaned and corrected any filtration problems, you must obtain proper water balance.

This will help in getting rid of the cloudy water in your facility. If your swimming pool water remains cloudy after correcting your filtration, flow rate, and pool water chemistry; then the most likely cause for your cloudy pool water now is suspended microscopic particles. Your next course of action at this point, is obtaining a good quality pool water clarifier.

Using this product in your pool water will allow the suspended particles to clump together. At this stage, the fine suspended particles are now large enough that they can be properly filtered out. Also by testing and correcting the other problems and causes of cloudiness in your pool, you will correct your problem with cloudy water.

Have you had to deal with cloudy water? Have a tip that worked for you? Tell us about it in the comments.

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  • Anon

    My pool has a lot of water bugs in them

  • Shaun McLane

    Those things are a huge pain. There’s really no easy way to get rid of those.

  • Karim

    Great article, thank-you. I have cleaned my filters and the chemistry is balanced. My pool is filled from a well source, which has fine mineral particles in it causing a turquoise haze (like Lake Louise). Although pretty to look at, I want that crystal clear sparkle we all crave. I’ll try a pool water clarifier and see if that clumps the fine particle sediment for filtration.

  • Sue

    Several years ago I had cloudy water that I could not get cleared.The filter system was working properly, all the levels were ideal, the filter was clean and clarifier did not resolve the cloudy water. I went to the pool supply to have them check the water and they got the same readings.The gentleman there told me to turn off the filtering system, broadcast alum over the pool, leave the pump off, vacumn to waste the next day and then adjust your levels. The alum takes the particle out but can also deplete your chemicals. This does work. Infact, I have a cloudy pool right now and have checked all of the above.I will use the Alum tonight.

  • Rehan Harmse

    About a month ago I had a swimming pool installed at my house. It is a fibreglass pool and the installers had it filled 2/3 with water during installation to get the inside outside pressure equal.

    It started raining and kept raining for about a week. When the install was completed and needless to say, the water was really awful, I asked the installer, well actually insisted that I want to clean the pool, you know……it would be my first pool clean.

    First I start of getting all pH levels right and once that was done, I ran the pump for 36 hours, Friday 18:00 till Sunday at roughly 06:00.

    All excited about my “supposed to be clear by now” pool, I woke up early that Sunday morning and to my utter disappointment, there I stood, starring at a dull creamy cloudy pool.

    What I did next, worked like a charm……

    I went and bought hth Xtreme Floc and poured half a bottle into my pool and ran the pump for about 3 hours on circulation to get it all mixed up a bit.

    I left the pool standing for about 12 hour so that all the particles drop to the bottom (DO NOT switch on your automatic cleaner, it will just mix it all up again….I did and I had to wait again)

    I took the inlet pipe and carefully sucked up the thick layer of “coffee” on the bottom of the pool to waste. I continued to about where the water was 2cm above the weir.

    I then topped up my water to the correct amount….I think, 2cm under the top of the weir and ran the pump for 6 hours. By this time it was already much better, BUT I HAD THAT PARTICLES YOU ASKED ABOUT!!!!

    I then added a floc block in the weir and ran the pump like normal (it makes the sand in the filter sticky, thus catching almost all those particles floating around)

    Lastly, someone told me to put a thick sock on the outlets to catch the real fine ones and I must say, that helped a lot.

    I am no expert, but this worked for me.