Pool water purification: how to choose chemistry and products

Recommendation points

Water is supplied to the pool from the general water supply system of the house (municipal or autonomous). The use of water from open natural sources is prohibited. And although the water is supplied clean, a whole range of measures is required for its preparation and purification at different stages of the pool operation..

Pool water purification: how to choose chemistry and products

First stage

At the beginning of the season or after the installation of the pool (before the start of operation), water samples are taken and submitted for analysis to a specialized laboratory. At this stage, samples are taken at two points: before filters and after filters..

Then the analysis is carried out regularly, and the number of samples increases to three – a study of water from the pool itself is added.

Pool water purification: how to choose chemistry and products

Based on the conclusion of the laboratory, recommendations are developed for the integrated application of all types of water purification, including making adjustments to the current scheme.

Before filling the pool with water, the walls and bottom should be treated with algicide. This prevents algae infestation. The first chemical treatment is done after filling the pool.

First week of operation

The pool is filled with water to the operating level determined by the position of the skimmer (cut-in, mounted or floating).

Primary disinfection of water is carried out with chlorine-containing preparations. The starting dose is calculated based on the total water volume and the recommended free chlorine content and the optimum pH level. The dosage is carried out in accordance with the manufacturer’s recommendations, and the parameters are controlled using testers.

Pool water purification: how to choose chemistry and products

The first week, control is done daily.

Factors affecting water quality

During the use of the pool, its biological pollution occurs. Hair, skin particles, secretions enter the water from a person. Plant spores and insects enter naturally. Bacteria and viruses are everywhere.

If the pool is open, then fallen leaves or flower petals can fly into it. There is also the usual dust and dirt. Therefore, cleaning should be done regularly..

Mechanical filtration

Primary or preliminary cleaning can be carried out with a skimmer. For example, a bucket-shaped mesh filter is placed in the tank of a mounted skimmer, which retains debris.

Pool water purification: how to choose chemistry and products

The main stage of cleaning falls on the filtering device. This type of cleaning is carried out daily and does not depend on the intensity of use..

The mode of operation of the FU is chosen so that the entire volume of water is purified twice. For water temperatures above 24 ° C – three times. The operating time of filters can be up to 12 hours, in some cases (with some types of chemical cleaning) – it can be around the clock.

Pool water purification: how to choose chemistry and products

Mechanical cleaning of the bottom surface and walls (without draining the water) is carried out using a bottom vacuum cleaner. It connects to the skimmer, which is then switched on to the regular cleaning mode..

Pool water purification: how to choose chemistry and products

The filters are cleaned when the pressure gauge readings are higher than the recommended pressure value specified in the manufacturer’s instructions. After using the bottom pump, the FU must be washed. Filter flushing is controlled visually – by the transparency of the water discharged into the sewer.

Chemical cleaning

This type is more complex and has 4 types of processing:

  • disinfection;
  • pH control;
  • preventing algae contamination of water;
  • removal of microscopic solids (coagulation).


In addition to the “shock” treatment at the beginning of operation, the water is regularly disinfected.

The most common reagent methods are chlorination and treatment with active oxygen (by the way, both types are generally widely used for disinfection). Of these, chlorination is more readily available. In addition, it has a more stable effect over time..

Pool water purification: how to choose chemistry and products

Another reagent treatment method, bromination, is not suitable for open water.

Ozonation gives very good results, but has a short-term effect. In addition, the use of “technical” ozonation is limited by the high cost of equipment and the extreme danger to humans of such a powerful oxidizer as ozone (even in small concentrations).

PH control

Reagent disinfection methods change the acidity level (pH). The level is adjusted using drugs that change the concentration of hydrogen ions (pH + or pH-).

Pool water purification: how to choose chemistry and products

Prevention of algae infestation

Conventional disinfection has little resistance to algae growth. Turbid water, plaque on the walls, unpleasant odor, favorable breeding ground for bacteria, increased load on filters – all this is a consequence of the appearance of algae.

In addition to the primary treatment with algicide of the pool itself, it must be additionally added to the water.


All mechanical cleaning filters have a certain threshold for the minimum size of the captured particles. The smallest fractions get into the water and are especially noticeable under artificial lighting with a pronounced direction of the light flux. The use of coagulants allows you to bind microscopic fractions and increase them to a size that filters react to.

Pool water purification: how to choose chemistry and products

Important! The natural loss of water must be compensated for by adding fresh water, otherwise the concentration of chemicals will constantly increase. It is recommended to add about 3% fresh water of the pool volume daily.


All chemicals for water purification are in concentrated form. Storage and work with them must be carried out in compliance with safety requirements.

Any contact with the skin, contact with mucous membranes, in the eyes can cause significant harm to health. In such cases, it is necessary to rinse these areas in running water, and in case of severe damage, go to the hospital..

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