Cloudy water in a swimming pool - what are the reasons?

Cloudy Pool water: Reasons, Signs and Recommendation to eliminate. 

Water care is not a difficult process and can be achieved through regular maintenance using the right products. To help you with identifying the early signs of this condition with your pool, below are the signs of cloudy water as detailed by our WaterStore customers through complaints.  

Characteristic #1: "The water in the pool is blue, but not clear, it's white. What should I do?"(Note: Some may identify watercolor as grey or milky water/whitish water, for the same condition) 

Milk-colored water is a fairly simple problem, which can be solved by specialized products. The tiny particles of impurities which were missed to be captured in the mechanical filters is the cause of this condition. In order to have them removed, these particles should be consolidated to a bigger form, which then is filtered and captured in the sand filter. Following the recommendations, dosage and instructions provided by an expert will help rid of the milky water.  

Chemical water treatment 

A coagulant or flocculant can help clarify the water, they are available in the form of liquid, granules and cartridges. 

Treatment process: The liquid form is suggested if the volume of the Pool water is 10-15 m3 and for pools not less than 25 m3, cartridges are recommended. After adding the agent, it is necessary to include a 6-position valve of the filter into the filtration mode. Every time a pool is treated with coagulant or flocculant agent, it is important to rinse the filter backfill multiple times. This ensures pH balance and for maintenance shock chlorination.

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Filter element replacement 

A small percentage of contamination may still remain post the flocculant process. This may indicate the need to replace the filter media. Manufacturers recommend changing the quartz sand every 1.5 - 2 years. When using a mounted filter, the filter bag must be replaced, as the rag fibers are stretched over time. In a cartridge type filter - the cartridge.  

The use of a coagulant clarifies pool water. The desired result can be achieved by replacing the sand filter with the glass, because it has been proven to clarify the water much better and also reduces the usage of chemicals, i.e., it facilitates the maintenance of the swimming pool. 

Characteristic #2: "The pool water is brown, there is rusty water coming from the well - the pool water is yellow." 

It is not uncommon to find metals in natural spring water. Considering that the water is drawn from a well, a red tinge or sediment is quite likely. High concentrations of metals in the water are harmful to the skin. Supplementary specialized products for the reduction of metals can help the water become clean and comfortable to swim in. There are various manufacturers of metal removal products available in our online shop.  

Please read the detailed instructions before using the product, which also specifies the ideal pH level and other factors that the pool should be at, for maximum effect of the treatment. 

This is particularly relevant for above ground pool users. A specialized metal remover (and other pool chemicals) will accelerate and facilitate bringing water to the ideal appearance. Chlorination helps remove metals, because chlorine oxidizes the metal ions, and they precipitate as flakes at the bottom, which can be easily extracted with a hand hoover.   

Characteristic #3 "The water is green. There must be algae, so what should I do?"  

There are various reasons for the appearance of algae in the pool: increased air temperature, rain and organic pollutants etc. Algae spores invade hard-to-reach corners of the pool and multiply extensively.  

Algae are of different species; some are easy to control, while others are not. Algae can be controlled using UV units, mechanical cleaning filters, hand and automatic hoovers for cleaning, and chemicals against water turbidity. 

Here is a list of most-common types: 

  • Green Algae: Most commonly found around the tabs and in the corners of the pool. a common problem found in outdoor pools. The easiest way to control green algae is to balance the pH level. The shock chlorine destroys single celled microorganisms, the procedure is then completed with shock algaecide. To ensure complete elimination of the algae it is important to wash the filter element (silica/glass sand or cartridge) and remove accumulated algae.

In cases of darker water, the time required is much more as this is a result due to neglect. Therefore, requires a lot more fixing, scrubbing the surface with a brush made of nylon or rubber bristles is suggested followed by a manual (skimmer) vacuum cleaner should be used repeatedly which helps picking up algae.  

  • Yellow algae: Found mostly in shaded areas. These are ruthless and harder to get rid of. The cells of yellow algae have an additional protective layer, therefore should be removed from the surface initially through mechanical means. They appear in the form of a film. As for the chemical treatment of yellow algae, the dose of the chlorine used should be twice. 
  • Rose and white algae are extremely rare and can only be removed mechanically. Usually, they grow inconspicuously near the embedded elements. 
  • Black algae: are hard to get rid of. It appears as dark green and black spots on the walls and the bottom of the pool. They are characterized by strong roots, which penetrate into the surface of linings (most often in tiles and mosaics), nozzles, and skimmers.

Black algae are resistant to chemicals. They require an experienced technician, time and patience to deal with.  

Algae damages the aesthetic appearance of the pool, increasing wear and tear of the equipment. It clogs the filter element, which must be washed. Worst of all, it is harmful to humans. They can cause intestinal distress and nausea, itching, and skin rashes when they enter the body. Therefore, it is important to regularly use an auxiliary remedy against the algae.  

Characteristic #4: "After chlorination the pool water is cloudy and has a sharp smell of chlorine, what to do?" 

When using stabilized chlorine to disinfect a pool, there comes a moment when the water becomes cloudy, and the smell of chlorine is pungent. This is called chlorine overstabilization - the increased presence of cyanuric acid in the water. It usually occurs in mid-summer or during the end of the season. The temperature in the air, number of swimmers, rainfall and warm days are some of the factors for this condition. 

Why does this happen? Chlorine evaporates and the stabilizer accumulates. Partial replacement of the pool water will help solve this problem. Approximately 30% of the total water volume should be renewed.  

Causes of water cloudiness  

The presence of organic contaminants in the water is a common cause of cloudiness. Pool water becomes cloudy due to excessive dirt and debris in the form of sweat, saliva, skin care products etc. It is important to do the basic checks - "Is the pH balanced?", "Has shock chlorination been done?", "What are the tester readings?". Because all of these actions have a direct impact on the water's clarity. 

Here are the recommendations to eliminate water cloudiness in a basic case (the most common one):  

  • pH level check: Which can be determined using a pH tester and then followed by a pH regulator to either increase or decrease the pH level as per the results found. Filtration then must be set to recirculation/filtration mode.
  • Implement chlorination with a shock agent. Filtration is switched on in the filtration mode. It is important to flush the backfill after the procedure and no swimming should be allowed for 24 hours.
  • After a day, add the long-acting product (Chlorine) to the skimmer or float dispenser. There are two types of long-acting chlorine – “no adds” and “multi-action”. The latter provides additives in the form of coagulant, algaecide, anti-lime besides chlorine.

If the pool volume exceeds 25 m3, we recommend adding extra algaecide and coagulants to the pool, because multifunctional chlorine may not be enough.  

Liquid pool chemicals are poured into the pool bowl, so they will not damage the liner. The granular form should be diluted in a container and poured around the perimeter of the bowl. Cartridges are placed directly into the skimmer.  

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High pH and chlorine deficiency in the water 

The benefits of chlorine are discussed, however, the clean water in the pool also depends on the pH level. Almost all references on water care indicate a precise procedure – begin with the ideal pH and then move to the other steps. 

Acid-alkaline balance is a very important aspect that is neglected in practice. If the pH level is too high, the chlorine product will not work properly. This makes it comfortable for microorganisms to grow and multiply. There occurs an absorption of more chemicals than is necessary. You may add more chlorine than stated in the instructions hoping that the cloudiness will "clear" the water. Imbalanced pH levels do not allow chlorine to fulfill its function. As a result, there can be excess use of chlorine - so in addition to the cloudiness, the water has a pungent chlorine odor.  

The pH compensation is necessary to avoid calcium deposits on the pool piping and equipment. Also, it is essential to increase the service life of the system. The wear and tear of the equipment happens over time, but the unpleasant feelings while swimming is immediate.  

Most commonly, imbalanced pH levels cause mucosal discomfort, such as burning eyes, nose, dry and itchy skin, people mistake it for chlorine, in reality it's more likely that the pH level is too high or too low. Comfortable swimming and effective disinfection are achieved when the pH level is between 7.0 and 7.6. Values that are lower or higher must be adjusted using the regulators. There are many factors that influence the pH level: rainfall, ultraviolet light, air temperature, and the number of swimmers.  

NOTE: With an imbalanced pH level, the use of chlorine, bromine, active oxygen is obsolete.  

Poor Selection of equipment or malfunction 

Selecting the right equipment goes a long way, possibly with a reserve, as choosing the wrong equipment can do more damage. A filter with the appropriate capacity, a pipe of the required diameter, the correct number of intakes and feeders.   

Pure water in swimming pools assumes serviceable and properly designed equipment in relation to the volume of water and chemical treatment: pH correction and pool disinfection on a regular basis. Following the appropriate water treatment regime - the water will be completely safe for swimming and pleasing to your eyes.  

Stay safe and enjoy your swimming pool.