Cloudy Pool Water – What Are The Causes? How Do I Treat It?

Cloudy pool water is a problem that is faced by almost all pool owners one time or the other. However, the key behind sorting this problem out is knowing the causes behind the same and the treatments that can help you in clearing it out. There are many things available in the market that can clean your pool for a short time. However, the cloudiness will return back in a short time. Here, in this article, we will discuss the source of this cloudiness and how to tackle it best.


Causes Of Cloudy Pool Water

There are several different causes that can cause the clouding of pool water. Let us take a closer look at them:

Imbalanced chemicals: An imbalanced chemical composition is one of the major causes of clouding up of pools. There are different imbalances that may occur such as calcium hardness, alkalinity, pH, chlorine level imbalance, or changes in cyanuric acid composition.

Faulty filter: Faulty filters cause poor filtration of the water. This can happen due to worn out or clogged cartridges of the filter or if there is scaling on the filter.

Mineral deposits or other environmental factors: The cleaning process of the pool water can also be impeded by the build-up of leaves, pollen, or dust. Other environmental contributors to the cloudy pool water are bird droppings, run-off water, or insects. Outside chemicals like silicates, sulfates, phosphates, and nitrates are often carried into the water by the runoff water causing cloudiness of the pool.

How Improper Chemical Balance Causes Pool Cloudiness

One of the trickiest parts of maintaining a pool is maintaining its pool chemistry. Let us understand how incorrect amounts of different chemicals can cause cloudy pool water or even algae.

Improper chlorine or pH balance: these are one of the common causes behind cloudy pool water. Though pH balance is not directly the reason, it can have a huge effect on the workings of other chemicals present in the water. A high pH can cause improper dissolving of calcium causing calcium scaling as well as pool cloudiness in both concrete as well as fibreglass pools. A low pH balance, in turn, makes the chlorine highly reactive depleting it fast and turning the water cloudy. This makes it ineffective in killing the algae, bacteria, or any other microorganism present in water.

High alkalinity: Monitoring of the total alkalinity levels should also be done. This is because a high TA level can cause imbalances in pH as well as calcium scaling. These often cause cloudiness of water. In order to raise the pH level to the recommended level, the total alkalinity of the water should be lowered through aeration by adding muriatic acid.

High calcium hardness: a high level of calcium hardness in pool water can cause a buildup of excess calcium. This does not get dissolved in the water and starts accumulating in the pool. The calcium scales can also clog the filter which further leads to poor filtration. This causes a buildup of dirty or cloudy water in the pool. In order to maintain clear water, do ensure to keep the calcium hardness levels between 200- 400ppm at all times.

Other chemical imbalances: In addition to the above-stated imbalances, there are several other chemicals present in the pool water that should be kept in check. Improper levels of chemicals such as bromine, phosphate, and cyanuric acid can also cause the cloudiness of the pool. In order to verify which chemical imbalance is causing the pool problems, there are several test kits available in the market. These digital water test kits save a lot of time and are highly effective for the regular maintenance of your fibreglass pools.


Solutions For Fixing The Cloudy Pool Water

There are several solutions available in order to fix cloudy pools. In order to choose the right way, you need to first understand the right cause behind the cloudiness. Let us now understand how to fix the different problems associated:

Chlorine stabilisers: Using chlorine stabilizers such as cyanuric acid helps in preventing the chlorine depletion that happens due to UV light. However, this is a strong chemical and should be used within the recommended limits. This is because if it exceeds the same, free chlorine disappears from your fibreglass pool and the water becomes cloudy.

Constant monitoring of Total alkalinity and pH: In order to maintain the optimum balance of pool water chemistry, you need to regularly monitor the pH level and total alkalinity level. For stabilizing the pH, there are pH increaser and pH reducer available in the market. In the case of Total alkalinity, you have to either get extra equipment or aerate the pools and add the muriatic acid to the water.

Cleaning of circulation and filtration systems: Poor water circulation system of a pool is also a big cause behind the pool cloudiness. In order to fix that problem, there are several things that can be done:

  • Make sure to point down the eyeball fittings or return fittings for proper circulation of water
  • Use the right sized pump for cleaning the water in an adequate way
  • Ensure that the filtration system runs long enough to keep the water clean.
  • Regular cleaning of your filter ensures that all the foreign particles are removed from the system and the water is cleaned in the right way.
  • Always backwash, clean, or replace the cartridge filter and D.E. on a regular basis.

Pool water circulation is also a big cause behind pool cloudiness…

Removing of foreign particles: In order to ensure that the environment is not the reason behind the clouding of the pool, follow the following practices.

  • Use nets regularly to remove all the visible particles from the pool. You can even use some of the pool clarifiers available in the market to clear up the water if the cloudiness still persists.
  • Scrub and clean the pool with a large leaf net to remove algae in its early stages. Follow that with a vacuum and a pool shock for any remaining algae growth.
  • Get a pool cover and chlorine stabilizer to avoid direct sunlight on the pool. This helps in stopping the fast depletion of free chlorine in the pool.
  • Pay close attention to the reduction in pool chemistry in case of rain and get it adjusted at regular intervals.
  • Adding algaecide: Algaecides are used to kill algae in its early stages. However, the best way to remove the algae is by scrubbing, cleaning, vacuuming, and killing the algae with shock. Algaecides should only be used once in a while in early cases.


In order to ensure the right water clarity and complexity, good research needs to be done regarding the same. If you follow the above-given steps, pool maintenance becomes an easy task. However, if the cloudiness issue persists, it is best to consult a professional. Not only do they help in getting your pool on the right track, they even have maintenance packages to save you the effort. The pools are for enjoyment, and keeping them in pristine condition helps you in getting the most out of them.

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