Disinfection of pool water - a complete beginner’s guide

Disinfection of pool water - step by step

Swimming has many benefits for health and welfare of a human body, as it directly helps with the respiratory, cardiovascular, musculoskeletal, nervous and immune systems. The swimming process is healthy only when the water is decontaminated and is enriched with useful elements. The water used for filling the swimming pool should always be filtered and disinfected irrespective of the source of water (Well, tap, municipal water etc.). Only then does the water be fit for swimming. 

During water treatment, make sure that the following aspects are paid close attention:  

  • Pool filtration system
  • Filter and backfill wear and tear
  • The operation of the disinfection system.

NOTE: filtration and disinfection can never be skipped for achieving a safe and clean pool water.  

What is disinfection?  

Disinfection of water is an adjustment of the necessary indicators. The purity of a clean Pool water is subject to change when it is exposed to the sun and environment. The indicators for adjusting the water quality in private and public pools are different. The requirements for filtering, checking the indicators and disinfecting in a public pool are much higher, the factors to keep in check are pH level, alkalinity, cyanuric acid, total hardness, free and bound chlorine. The said factors can be measured using electronic testers – photometers.  

Private pools must be corrected by two indicators:   

Ideal pH level


Why are these indicators so important? The pH of the water is one of the most important factors affecting its equilibrium. An imbalance to the pH level leads to overuse of chemicals for disinfection (chlorine, active oxygen, bromine), corrosion of equipment, water clouding, discomfort to swimmers (burning eyes and mucous membranes). Chlorine is a direct disinfectant. 

Determining the existing indicators  

To begin with, you need to equip yourself with a water tester. The testers come in droplet, tablet, and strip type. The kit will always include everything you need to measure: a reagent and a scale with an indicator. Take water into the tester tube at a depth of 30-40 cm "by the elbow" - It is important not to take water directly from the surface, its index will be worse. 80% of the contaminants such as hair, grease, saliva is always found on the surface. The instruction in the user manual helps one determine the indicators from the sample taken 

Ideal value chart: 

pH in the range of 7.2 - 7.6

chlorine no less than 0.3 - 0.6 mg/l

How to regulate the pH level?

If the pH level is too high, they should be lowered, and if it is too low, they should be increased. Which can be done by using pH regulators. In most cases, the pH is higher than standard and needs to be lowered.  

Having determined which indicator to correct, we begin to work on the preparation of safe water. The pH and the chlorine should be at its ideal measurements before introducing other prophylactic agents against algae and cloudiness. The process remains unchanged irrespective of the disinfectant used. Adding disinfectants before adjusting the pH will result in poor to no effect. The water indicators must be checked not immediately, but after passing at least one water circulation cycle of filtration systems.

pH down for swimming pools pH plus for swimming pools

  How to regulate the chlorine level  

Chlorine disinfection is the most common, it is both efficient and affordable. There are two stages of chlorine disinfection:   

Stage 1: Shock chlorination 

Stage 2: Long-acting chlorine  

Stage 1: Shock treatment is the primary water disinfection. During shock chlorination, the concentration of chlorine in the water reaches a level of 2.0 - 3.0 mg/l. No swimming is allowed at this level. The shock chlorination process uses tablet or powder forms of shock chlorine. It is tasked to kill all germs, bacteria and viruses.   

Stage 2: To maintain the remaining chlorine in the water within the norm, use a long-acting chlorine. It comes usually in the form of 200 g, 250 g, 20 g tablets or powder. Long-acting chlorine is put in the basket of the intake device (skimmer) or float. It slowly dissolves, saturating the water with chlorine. Long-acting chlorine tablets are often multifunctional. They contain not only chlorine, but also an algicide, a flocculant, etc.   

Chemoclor T-Tabletten Chemoform Oxichlor Chemochlor Multi-Tabletten

Chlorine FREE pool disinfection 

Chlorine-based pool chemicals are undoubtedly recognized as the best disinfectant. However, there are a number of reasons why some people prefer water treatment without chlorine. Among them are-high sensitivity to chlorine preparations, aversion to the smell of chlorine (even a slight one). Considering this, let's have a quick look into the alternatives to chlorine. 

Bromine is one of the alternative products to chlorine. However, it works slower than chlorine and the effect take longer to showcase. Bromine destroys pollutants by ionizing or separating them at the molecular level. Most of it remains effective even after this process, so it lasts a little longer than chlorine. Due to this, the common practice is to use chlorine for shock, prophylactic water treatment and bromine for long-term treatment.  

Active oxygen - a chlorine-free, active oxygen-based pool water purifier eliminates bacteria and viruses caused by pollution sources such as sweat, urine, cosmetics, etc. The effectiveness of a disinfectant is determined by the rate of destruction of pathogenic organisms. A chlorine-containing product shows a higher rate than chlorine-free pool agents. 
For appropriate disinfection, the concentration of active oxygen in mg/l must be much higher compared to chlorine. Additionally, these kinds of products are suitable for use in domestic swimming pools, they are not approved for public ones.  

When selecting products for a pool, it is very important to prioritize the concentration, consumption, and frequency of addition over the price of the product. It is recommended that using an expensive product is much more convenient due to the high concentration and lower consumption. 

Chlorine free bromine for pools Chlorine free sanitizers for swimming pools

Let's make swimming healthy with the right choices!