Why Does Pool Water Turn Cloudy?

How To Fix Cloudy Pool Water

If you own a pool, you probably know that the bright, crystal clear water can turn into an annoying eyesore of hazy or cloudy water overnight. The pool is not only unpleasant but can easily lead to a number of problems including:

  • Discomfort and swollen eyes for anyone swimming

  • Short filter cycles that require frequent cartridge cleaning

Hazy pool water is not necessarily due to poor maintenance. Some of the factors that contribute to the problem include:

  1. Pool Chemicals
    Poorly balanced pool chemistry can cause the water to turn cloudy due to low or high chlorine levels, high alkalinity, high pH, or increased calcium hardness levels. Failure to achieve the proper chemical balances causes contaminates and other unwanted particles to multiply in the water, turning it cloudy.

  2. Pool Shocking
    It is not unusual for pool water to turn hazy after shocking, but it should clear on its own if you keep the filter running as required.

  3. Filtration Problems
    A faulty filter system or failure to run the filter for the required 8-10 hours per day may cause the water to turn hazy. Keep in mind that the pool filter system is intended to constantly clean pool water. If it’s not continually cleaning and circulating the water, then the stagnant water will begin to turn cloudy.

  4. The Environment
    Your pool’s surroundings can also influence the quality of your pool water. Factors such as precipitation, vegetation, birds and insects droppings, pollen, weather, sun, people, nearby construction work, and pool algae can contribute to turning the water hazy.

    Any of these factors can cause an unusually large number of tiny particles in the pool that reflect light, giving the pool water a cloudy appearance. These particles are extremely small, between 0.5 microns and 5.0 microns, which is about one-thousandth of a grain of sand. They are also negatively charged, meaning that they exist in isolation rather than lumping together.

How To Clear A Cloudy Pool

The key to fixing a cloudy pool is identifying the cause of the problem. If the filter system is running properly and for the required amount of time—assuming that you have the right equipment for your size pool—then administering the right dose of water clarifier and/or flocculants should clear the cloudy pool.

Clarifiers and flocculants work by neutralizing the electric charge (negatively charged particles) so the particles bond together and become large enough to be caught in the filter system or heavy enough to sink to the bottom where they can be collected when vacuuming.

You should, however, make sure to use the right amount of chemicals. An excess amount will neutralize and reverse the charge, causing the pool to appear cloudier.


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