How to Keep Pool Water Clean

A complete guide for Above Ground Pool owners, Inflatable pools, Kiddie pools, and other small pools.

Above Ground Pools

Guide to Above Ground Pool Maintenance

How do I keep my pool water crystal clear and prevent it from turning green or cloudy?

On this page you will find answers to the following questions:

  • How to keep inflatable pool water clean?
  • How to keep a kiddie pool clean?
  • How to keep a small pool clean without a filter?
  • How to keep pool water clean naturally?
  • How to keep a pool clean cheaply?
  • How to keep a pool clean without chemicals?

The most effective , economical and environmentally friendly method of maintaining clean water in private pool is with certainty the method of ionizing water by electromagnetic field. Read more

4 Methods to Purify Your Water

Comparison Table For Water Purification Methods

Consider these water treatment methods in more detail

Keep the water clean in the pool with chlorine



Chlorination of water is based on the addition of chlorine-containing substances into water; this is the oldest and most reliable reagent method of water disinfection. This method is based on the ability of free chlorine and its compounds to inhibit enzyme systems of germs, catalyzing redox processes. In 98% of all cases in the world water is chlorinated at least to some extent in any swimming pool even in the pool with sea water, since chlorination is the most reliable and affordable way to comply with the accepted sanitary standards.

Advantages of Water Chlorination
  • Reliability and a wide range of effects on microorganisms. Chlorine is able to destroy the overwhelming majority of known pathogenic microorganisms. Chlorination processes not only the water, but the surface of the swimming pool as well and in contrast to ozonation, electrolysis and ultraviolet treatment when only water passing directly through the decontamination unit is processed but the pool surfaces remain a risk factor.
  • Long validity of this method. Chlorine is retained for long time in active form in water (free chlorine);
  • This is inexpensive and affordable method.
Disadvantages of Water Chlorination
  • Spore forming microorganisms are not destroyed by chlorination
    (in contrast, for example, from ozonation).
  • While maintaining constant level of chlorine in water over the time the pathogens are
    getting used to these chlorine concentrations. In order to solve this problem periodic treatment with higher doses of chlorine (chlorine shock)
  • Very toxic products of chlorination are constantly formed in water (chloroform, chloramines), with which it is necessary to fight. Also chloramines irritate eyes and skin and can cause severe illnesses.

Water Disinfection Using Salt Electrolysis or So-Called“Sea Water”



Chlorine appears again. But the presence of salt in water alone does not give anything except for corrosive activity of water. Therefore, so-called “facility for sea water” is used. Specifically, this facility is called a chlorine generator, and its task is with the help of electrolyses to take apart NaCl into Na+ and Cl-. Actually the whole task is to get free chlorine, which in its turn gives us -Cl2+H2O = 2HClO, same hypochlorous acid which can be added directly in form of tablets or granules.
There is no other fundamental difference between disinfection of water with chlorine and using chlorine generator.

Advantages of Method of Disinfection Using Salt Electrolysis:
  • Effectiveness of chlorine disinfection;
  • Cost- effectiveness (salt is used as raw material);
  • There is no chlorine overdose so chlorine is produced gradually, but not injected by impulses;
  • Maintaining the right concentration.
Disadvantages of Method of Disinfection Using Salt Electrolyses:
  • Surfaces of the pool remain a risk factor since only water passing through device is disinfected;

Salt water in the pool has the highest corrosive activity!
If swimming pool is filled with salt water everything will rust that can rust! Countercurrents, ladders, heat exchangers and other equipment made of steel. Special types of equipment that is resistant to corrosion is used in pools with salt (sea) water.

Water Ozonation



Ozone is gas which is the most active form of oxygen. Ozone is one of the most powerful oxidants, which destroys bacteria, spores and viruses.
Essentially water purification by ozone is equivalent top repeatedly accelerated procedure of natural water purification.

Advantages of Water Ozonation:

Wide range of effects on microorganisms ( ozone destroys actually all bacteria, viruses and organic substances), and activity of ozone is many times higher than of oxygen and chlorine. For example, pathogenic microorganisms are destroyed by it 15-20 times and spore forms of bacteria 300-600 times faster than by chlorine. The virus of poliomyelitis dies at ozone concentration of 0,45 mg/L in 2 minutes while from chlorine, twice the concentration in only 3 hours;

  • Chloramines irritating skin and eye mucosa do not form;
  • Unlike chlorine, ozone does not leave any odor;
  • Ozone treatment makes water shiny and gives it a blue tint (chlorination gives green tint);
  • Ozone overdose is not a problem since after the end of treatment ozone is converted back into oxygen;
  • Ozone treatment does not give water any additional foreign substances and chemical compounds.
Disadvantages of Water Ozonation:

Ozone does not have prolonged action because it is unstable gas and it rapidly decomposes into normal oxygen without accumulating in water environment;

  • Water ozonation is much more expensive than traditional chlorination;
  • The surfaces of the pool remain a risk factor, because only water passing through the device is disinfected;
  • Ozone is toxic by inhalation; at high ozone concentrations disorders are observed in respiratory tract, lungs and mucous membranes;
  • Requires constant chlorination.

Chronic effect of micro-concentrations of ozone on human`s body has not been sufficiently studied yet. What is more, pure ozone is explosive. For these reasons, work with ozone requires careful safety control.
This method of water disinfection is ineffective for swimming pools with temperature above 80F(27 ̊C)

Water Treatment by Ultraviolet Radiation



Chlorine Free Swimming Pool method.
Nowadays ultraviolet irradiation of water is one of the most promising reagentless methods of water disinfection. Ultraviolet disinfection of water occurs with the help of ability of ultraviolet radiation to penetrate through the walls of the cell reaching its information center- nucleic acids of DNA and RNA. Ultraviolet disinfection of water lay in the absorption of radiation rays by nucleic acids; in this case DNA and RNA of pathogenic microorganisms loose the ability to divide, in other words the reproductive ability of the cell is lost. Ultraviolet water disinfection is considered to be one of the cleanest methods of water treatment.

Advantages of Water Treatment by Ultraviolet Radiation:

-Ultraviolet radiation has high efficiency in relation to pathogenic microorganisms, bacteria and viruses; it decomposes organic substances;
-Microorganisms do not develop resistance to ultraviolet radiation;
-Ultraviolet radiation decomposes chloramines;
-Ultraviolet Radiation even in high doses does not change chemical composition of water (unlike oxidative methods), it does not lead to formation of harmful chemical by-products; -This method is safe for health;
-Method of ultraviolet disinfection is quite economical.

Disadvantages of Water Treatment by Ultraviolet Radiation:

-It is necessary to control level of iron and carry out water purification if necessary; -Some organisms have high resistance to ultraviolet radiation;
-If there is coarse admixture in water, it can play a role of a kind of a shield for pathogens that will not receive the necessary dose of radiation. In these conditions, it is necessary to use additional stages of water purification for qualitative disinfection (in order to remove admixtures); they must be preceded by ultraviolet disinfection;
-Surfaces of the pool remain a risk factor since only the water passing through the device radiating ultraviolet rays is disinfected;
-Ultraviolet disinfection simultaneously during direct exposure , in other words it does not have prolonged action;
-Requires constant chlorination.

This method of disinfection is poorly efficient for swimming pools with temperatures above 80F(27 ̊C).
Such combination of methods allows to reduce the content of free chlorine in water, which is necessary for quality disinfection, and also to reduce concentration of chloromines.

Ionization of Water in the Pool by a Weak Electromagnetic Field



Purification of water in the pool by the weak electromagnetic field is one of the most advanced effective methods of maintaining clean water in private pools today.
The principle of operation is based on the polarization of water molecules, that is based on the effect of a weak electromagnetic field of water molecules in order to prevent the development of bacteria and seaweed.

Advantages of Water Ionization by Weak Electromagnetic Field:

Water remains pure for a long time cleaning the pool water which reduces the need for additional water disinfection with extra chemical reagents, chlorine in particular;

  • Quality of water after ionization almost meets quality standards of drinking water;
  • You can completely refuse from the use of chlorine substances in small pools when using an ionizer;
  • Absence of odor;
  • There is no skin irritation, mucous membranes of eyes and respiratory tract; -Absence of allergic reactions;
  • It is easy to use;
  • Cost-effectiveness;
  • Unlike other ionizers it does not require electricity;
  • Does not require continuous chlorination.
Disadvantages of Water Ionization by Weak Electromagnetic Field:
  • Additional chlorine disinfection may be required with water temperature above 80F(27 ̊C).
  • It is necessary to do preventive maintenance with chlorine 1-2 times a year.

This method of ionization with a small dose of chlorine (with water temperature above 80F(27 ̊C) is the most effective and cost-effective method of maintaining clean water in private pools nowadays.