Causes and treatments for cloudy pool water

Posted on Friday, 4 March 2022

Professional tips and solutions to treat cloudy pool water, as well as the main causes of this.

Cloudy pool water is caused for several reasons: For example, an excessively high pH level, the hardness of the water, too much lime, poor filtering, or too much organic waste. Another cause can be the build-up of microscopic algae. 

Cloudy water is essentially because of particles resting on the surface. There are different solutions to fix this.

At CTX, we advise you on how to resolve this problem for a clean, transparent, and clear pool water. 

To prevent and avoid cloudy pool water we need to undertake a series of maintenance and cleaning duties, with products such as those offered at CTX. You have to bear in mind that, even when the maintenance any hygiene of our pool is done correctly, there is still the chance of having cloudy water. That is why this specific problem needs specific solutions.

Cloudy pool water: causes and solutions

If we focus on each of the specific causes of cloudy water, we find the following:  

  • pH. The balance and adjustment of pH levels are essential to prevent corrosive or irritating water, as well as to prevent the reduced efficiency of disinfectant products. The recommended pH levels are between 7.2 and 7.6. To deal with this specific cause of cloudy water you should measure and adjust the pH level for each specific product: CTX-10 pH Minus  and CTX-20 pH Plus. You could also use the pH liquid reducer CTX-15 or the pH liquid enhancer CTX-25.


  • If there is too much alkalinity in the water, the pH is unstable and can lead to cloudy pool water, which happens when there is too many carbonates. An optimum level of this can be very helpful when balancing out the pH levels. CTX offers CTX 21 Alka Plus to increase alkalinity, if it is low, and this balances out the pH levels.

  • Excessively hard water. This is down to excessive calcium and magnesium in the water. The more there is of these elements in the water, the harder the water will be. To prevent this, it is important to prevent lime in the water. CTX has a range of descaler products, such as CTX 600 Antical  and CTX 700 Antical Super. This is the most common solution for cloudy and misty pool water.
  • It is also essential to analyse the chlorine levels in a pool, be they free chlorine, which is a disinfectant (ideal levels between 1 and 2ppm), residual chlorine, which no longer has any effect (maximum level of 0.2ppm), or total chlorine, which is the total amount of chlorine in the water, this must not exceed 1.5ppm. At CTX we have a range of measurement tools, as well as chlorine neutralizers if we have an excess of chlorine.
  • Microscopic algae, among other issues, can cause brown water. For this, CTX has a wide range of algicides available to deal with this issue.


  • Another of the most common causes of cloudy pool water is dirty filters. CTX offers a liquid product for sand filters to combat this problem.


Therefore, the solution to cloudy water is as follows: 


  1. Analyse the different water parameters to check the pH levels, alkalinity, chlorine levels, and water hardness.
  2. Backwash the filter to remove any dirt or grime.
  3. Adjust the pH level to between 7.2 and 7.6, if needed.
  4.  Add 15gt of CTX-200/GR ClorShock  for each m³ of water. Shock chlorine is a quick and highly effective disinfectant. 
  5. Add 1l of CTX-41 Flocculant for each 100 m³ of water. The flocculant or water clarifier is essential in all of these cases. 
  6.  Leave the filter running for 24 hours to resolve the problem.

To combat the problem of cloudy water or any other pool issues, you can rely on CTX’s specialist products and expert advice.