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Swimming Pool Chemical Treatment Methods

Points to Consider Before Chemically Treating Your Swimming Pool

Swimming pools need to be chemically treated to maintain pool water balance and hygiene. Pools that are not treated with chemicals regularly are unhygienic and may give rise to various waterborne illnesses ...
Gardenerdy Staff
Last Updated: Aug 30, 2018
Irrespective of the pool type, swimming pools must be sanitized regularly. Swimming pool chemicals disinfect the water and keep it sparkling clean. Sanitizers and disinfectants help control the growth of bacterial and algal matter in the pool water.
Proper chemical treatment will eliminate skin and eye irritation, and will help maintain the pool in general. The factors that have to be kept in mind while chemically treating pool are as follows:
pH Balance
The pH level is the measure of acidity or alkalinity, and needs to be tested twice a week. The pH level in the pool water must be slightly alkaline, that is a pH of around 7.2-7.6 must be maintained. It is at this pH level that chlorine is most effective.
Moreover, this level is similar to the pH of our skin. Too acidic water will corrode the metal equipment, resulting in etching of surface materials. Skin irritation is also caused. Water when too alkaline results in scaling of the pool surface and plumbing equipment, leading to cloudy water.
The pH can be controlled by adding either an acid such as muriatic acid, or an alkali such as soda ash or baking soda. The addition of alkali or acid will depend on whether the water is too acidic or too alkaline.
Chlorine Level
Chlorination is done to sanitize the pool water. Chemical compounds like calcium hypochlorite or sodium hypochlorite are available which provide chlorine to the water. When these compounds are added to the water, chlorine from the compound reacts with the water to form several chemicals such as hypochlorous acid.
This hypochlorous acid kills pathogens and disinfects the pool water. Pool experts recommend that these compounds be added with the help of a chemical feeder, after the filtration process. This is to ensure even distribution of chlorine in the water.
Direct addition into skimmer boxes can lead to concentration in those areas. Chlorine is available in tablet, granular or liquid form, and all work in the same manner. Even bromine can be used to disinfect the pool. The level of 'free' chlorine that has to be maintained in the pool is 1.0-3.0 ppm.
Shock Treatment
When chlorine compounds are added to the pool water, hypochlorous acid is formed which kills the bacteria. However, this hypochlorous acid is unstable and degrades when exposed to UV light from the sun. To counter this instability, a stabilizing agent called cyanuric acid is added to pool chlorinators, which minimize the degradation.
However, despite all these efforts, hypochlorous acid may still combine with other chemicals such as ammonia to form chloramines. Chloramines are not only poor sanitizers, but they also cause skin and eye irritation. An unpleasant smell is also present in the water, which indicates there is very little free chlorine in the water.
Shock treatment is important to destroy combined chlorine compounds (free chlorine is needed, not combined). The packages are available in local pool shops. As per the instructions on the package, the pool can be 'shocked' in evenings. This raises the free chlorine level in the pool, and also destroys germs, making the pool sparkling and attractive.
Calcium Hardness
Water too low in calcium becomes corrosive, while water high in calcium causes scale formation. Thus checking calcium hardness is very important. This test has to be conducted at a local pool store, as the standard testing kit does not test for calcium hardness. A sample of the pool water needs to be taken to the local pool shop and tested once each month.
Clarifier Addition
Several dirt particles and debris, too small to be caught in the filters, cause the pool water to become cloudy. This annoying cloudy pool water problem can be treated by adding a dose of clarifier to the pool water.
Clarifying agents make the tiny particles stick to each other and form larger particles. These larger particles can then be discarded by vacuuming or filtration. Clarifiers should be added once a week.
Metal Out Addition
Tiny metal particles that surpass the pool filtration system are found suspended on the surface of the water. This can be eliminated by adding a weekly dose of 'Metal Out' to the pool water. 'Metal Out' is a chemical that removes metal particles from the water.
Total Alkalinity
Addition of baking soda will help maintain correct total alkalinity of the water. This will in turn prevent sudden changes in the pH levels of the pool water. The total alkalinity of the pool water must be adjusted to 80-120 ppm.
Algaecide Addition
A dose of algaecide must be added to the pool once a week to control algal contaminants. Good quality algaecides combat various algal formation and destroy them without damaging the pool tiles.
This treatment should preferably be done the morning after the shock treatment. Algaecides are available in standard and highly concentrated formulations depending on the size of the pool and treatment required.
Proper chemical balance maintenance is a continual process and has to be done on a regular basis. This is because pool water is constantly being dirtied by oil from a swimmer's body, chlorine shots, substances that fall into the water and alter its chemical composition, etc.
Circulation of pool water keeps the pool chemicals mixed and even reduces algal growth. Investing in swimming pool safety covers or solar covers helps reduce chemical evaporation from the pool water. Chemical control units are also available, which regularly test the water chemistry and fix the balance automatically.