How to choose a filter for a pool: types of units and rules for choosing wisely

Your own swimming pool on the property is a source of inexhaustible joy and good mood, as well as a place where you can relax after a hard day at work. But in order for it to remain clean, you should be extremely careful about its arrangement. Agree, untimely water purification and disinfection can turn a pool into a source of serious danger to the health of swimmers.

To prevent this from happening, you need to be very responsible when choosing water purification equipment. A correctly selected pool filter will not only significantly improve the quality of water, but also save money intended for disinfection work. We will talk about methods of water purification and what equipment is used for this purpose.

Useful recommendations for choosing filter equipment, as well as advice from experienced specialists, are presented in our article. And the photographs and videos provided will help you better understand how to independently purify the water in the pool.

Water Filtration Options

Water circulation and the use of filtration units are the key to high-quality operation of any pool. Based on the method of water intake, skimmer and overflow pools are distinguished.In each of them, water is taken for purification from the bottom and from the top.

In this case, the fence from the bottom is the same for each type of pool, and the fence from the surface is slightly different.

Option #1 - filtering water in an overflow pool

The water splashing out of the overflow pool bowl ends up in special drains, which direct it first to the tank, and only then to filtration.

The peculiarity of the pool is that the water surface is at the same level as the edge. The lion's share of pollution is initially located in the upper layer, so the dirtiest water ends up in the drain.

When there is a large concentration of swimmers in the pool, maximum water movement is achieved and intensive splashing over the side is ensured, along with the lion's share of contaminants.

If there is no movement in the pool, then there is no flow of water into the drain. In this regard, this cleaning scheme is ideal for stationary structures. It is not applicable for frame and inflatable pools.

Option #2 - filtering water in a skimmer pool

The suction holes of stationary skimmer pools are located on the top of the walls. In frame and inflatable pools, skimmers are immersed to a shallow depth, hanging directly on the side.

With this method of intake, the water surface is located 0.2-0.3 m below the top of the side. The main disadvantage of such water selection is that due to the low location of the nozzles, surface contaminants are poorly removed.

The recessed location of the suction nozzles of skimmer pools often causes ineffective removal of surface contaminants located on the surface of the water surface

No matter how effectively surface cleaners work, some of the contaminants will in any case fall to the bottom in the form of sediment. To remove settled contaminants, it is necessary to ensure that water is drawn from below and supplied to the filter.

The problem is solved by constructing bottom ladders through which water is transported to filtering devices.

The number of water intake wall and bottom holes depends on the volume of water in the pool, the degree of contamination and the intensity of operation. In this case, the rule must be observed: 3 parts of water are supplied to the filter from the top part, and 1 part from the bottom.

The bottom holes perform another important function - they provide complete or partial drainage of water. This procedure is necessary for disinfection, mechanical cleaning of the walls, major work or conservation of the pool.

Healthy: Which pool is better, Bestway or Intex, comparison of quality and price.

Option #3 - cleaning using a filter unit

The water collected through skimmers and bottom holes is supplied to coarse filter, then under the influence circulation pump moves for finer cleaning to the filter station.

The system may also have a bacterial cleaning agent (ozonizer, chlorine generator, etc.), and a device for heating water. After passing through all stages, purified and heated water is supplied to the pool bowl.

Filtration is an excellent way to purify water from impurities, and therefore having a high-quality filtration unit is an integral part of any pool

The purified water input area is determined by the type of pool.In overflow varieties, the injection zones are located at the bottom, and in skimmer types, on the side opposite to the location of the skimmers. Such placement of injection zones ensures better water circulation and uniform cleaning.

What to look for when choosing a filter?

The main criterion to be followed when choosing a pool filter is throughput. This value is calculated in liters or cubic meters of water purified by the system per hour of operation.

With the help of modern pool filters, you can filter out even microscopic inclusions, not to mention large particles. The degree of purification is determined by the filtration speed and the type of filter used.

At a lower speed, the maximum degree of water purification is ensured. In this case, the basic rule must be observed: the entire volume of water must pass through the filtration unit at least three times.

The water that passes through the filter unit is free of small inclusions of various types of debris. Moreover, purified water is safe for swimming not only for adults, but also for the younger generation

At choosing a pump it is necessary to focus on the volume of the pool. It should be taken into account that an increase in the speed of water passage through the filler leads to a decrease in the quality of cleaning. Obviously, for a powerful pump you need to select a filler with a large capacity.

Modern cleaning units and filters are sold as a set, so there is no need to match the container to the pump or vice versa. Determining the performance of a filter is quite simple. To do this, the total volume of water in the pool must be multiplied by 2.5 and divided by 10.

For example, let's take a pool measuring 10x4x2, which holds 80 tons of water.We calculate: 80x2.5/10=20 cubic meters/hour. The filtration unit for the pool should be selected based on the calculated capacity.

Types of Pool Filters

Depending on the material used for filtration, the following pool filters are distinguished:

1. Mechanical;
2. Chemical;
3. Electrophysical;
4. Combined.

Each of the presented filters can only partially solve the problem of water purification. That is why filtration systems consisting of several different types of filters have maximum efficiency.

No. 1 - mechanical filters for pools

The following materials can be used as a filter element for mechanical filters:

• sand;
• woven or non-woven membrane;
• Activated carbon.

The principle of operation of a mechanical filter is quite simple - a membrane, layers of coal or sand, passing water through themselves, retain the lion's share of contaminants. The output is purified water, which has lost almost all impurities.

All pool filters operating on the principle of mechanical cleaning can be classified as follows:

• sand;
• cartridge;
• diatoms

This cleaning option is suitable for small pools up to 10 cubic meters. In large pools, in addition to mechanical cleaning, you will have to use chemical cleaning.

Sand filters

Sand filters are the most affordable and simplest cleaning systems. Typically, a filter consists of a closed plastic container with two holes for water to enter and exit.

Most often, the tank is filled with quartz sand, which serves as a filter material.

Factory-produced sand filter pumps are used for purification and recycling of purified water in inflatable and frame prefabricated pools. Change the sand in the unit every five years

Organic impurities and mineral salts are easily retained in the filter layer of quartz sand. The same thing happens with the chemical compounds that are formed as a result of pool disinfection.

The disadvantage of such a filter is its ability to trap particles not exceeding a size of 20 microns. Service life – no more than 3 years.

You can increase the service life of a sand filter to 5-6 years and increase the degree of water purification by replacing quartz sand with glass sand. A combined backfill with a heterogeneous composition, in which alternating layers of crushed stone, gravel and sand are successively located, has proven itself even better.

The pool sand filter is easy to maintain; cleaning is done by flushing using a reverse pump.

Another advantage is that a sand filter is easy to make with your own hands. The homemade assembly process is discussed in detail In this article.

Lime deposits can be removed using special agents introduced into the filter for several hours with the pump turned off. Finally, you need to carry out the standard washing procedure.

A higher degree of purification can be achieved using a sand filter by arranging successive layers of pebbles, crushed stone and sand.

The low cost and ease of maintenance of the sand filter make it the most versatile and widely used by pool owners. However, it also has significant disadvantages - heavy weight, impressive dimensions.

As an example, consider a sand filter with a pump from the Bestway brand, which produces swimming pools.

Models from the same manufacturer may differ in design and functionality, so please read the instructions before installation.

Current prices for sand filters:

Cartridge filters for pools

The role of the working element of this cleaning system is performed by the thinnest membranes made of propylene plates.

They successfully retain organic particles ranging in size from 10 microns, mechanical salts and salts of mineral origin. The efficiency of water purification with a cartridge filter is almost twice that of water purification with a sand filter.

The main advantage of the cartridge filter is that it is easy to remove from the flask and wash, and, if necessary, replace it

A cartridge filter is a box or flask with a hinged or removable lid, inside which a cartridge is installed. The flask also contains a small plastic bag designed to store filtered debris.

The main advantages of a cartridge filter:

• Compactness;
• High degree of water purification;
• Duration of operation;
• Lack of backwash function.

Once contaminated, the cartridge should be removed from the flask and washed. Depending on the volume of the pool, the service life of the cartridge varies between 3-12 months. For the cleaning system to work effectively, you need to have a supply of several replaceable cartridges.

Often, modern cartridge filters are mounted in one housing of a portable cleaning system, hence another name for cleaning equipment - filter pumps.

Despite their high degree of purification and ease of maintenance, cartridge filters are less popular than sand filters, which is due to their higher cost.

Current prices for cartridge filters:

Diatomite cleaning filters

Diatomaceous earth (diatomite) filter is the most expensive among mechanical cleaning filters.

The role of the filter element is diatomite ground into powder - a siliceous sedimentary rock consisting of weakly compressed or slightly cemented hollow shells of ancient microorganisms and decomposition products of algae of similar age.

Diatomite powder undergoes heat treatment before use - it is calcined in an oven at a temperature of 1200 degrees for at least a day. This treatment allows not only to eliminate all traces of organic matter, but also to obtain an excellent fine filter mixture of uniform composition.

With the help of a diatomaceous earth filter, not only maximum purification of the pool water occurs, but also its enrichment with silicon, which is due to the special conditions for processing prehistoric organic matter, which is millions of years old

Diatom filters are available in two versions. In the first case, the filter structure is similar to the structure of a sand unit. The only difference is that instead of quartz or glass sand, a backfill of diatomaceous earth powder is used.

In the second case, the filter unit is a system of cartridges arranged in series in one housing through which water is pumped. This device allows you to purify water as much as possible, removing contaminants from it, the size of which is only 1-2 microns.

Diatomite (kieselguhr, rock flour, infusor earth) is a loose or slightly cemented sedimentary rock, passing through which water is not only purified, but also enriched with silicon

Due to the ability of diatom powder to enrich water with silicon, its use for cleaning can reduce the use of chemical cleaning agents by 75-80%.

As you know, silicon water has high healing and rejuvenating qualities. That is why such expensive diatomaceous earth filters effectively compete with cheap sand cleaning systems.

Current prices for diatomaceous earth filters:

No. 2 - chemical water purification

With chemical filtration, water is purified by exposure to reagents. Depending on the filter model, from one to several cleaning operations can be performed.

Chemical water purification helps neutralize germs and bacteria; it can be used to make water more useful by saturating it with oxygen.

The greatest efficiency can be achieved with complex chemical filtration of water:

• chlorination;
• bromination;
• iodization.

Pool owners most often use chlorine as a bacterial protection - the cheapest and most effective disinfectant.

The main disadvantages of chlorine:

• unpleasant odor;
• causes allergies;
• does not destroy spore-forming microorganisms;
• capable of creating toxic compounds (chloramines and chloroform).

Despite a number of disadvantages, chlorine remains the most popular chemical water purification agent. It quickly evaporates, so after just a few hours not a trace remains of it in the pool bowl, which means that the unpleasant odor and allergies go away. Toxic compounds are easily removed with comprehensive cleaning.

In terms of cleaning efficiency, bromine is in no way inferior to chlorine. True, its cost is much higher, but there is no smell. When properly dosed, water bromination is absolutely safe for humans.

During the cleaning process with bromine, unpleasant odors are removed, bacteria, fungi and viruses are destroyed, water hardness remains unchanged, and high cleaning efficiency is achieved when the pH value deviates towards a higher content of acid or, conversely, alkali.

A separate category of chemical water purification products are represented by special flocculant preparations. Their main task is to enlarge small contaminants and fat residues to a size at which they can easily be captured by mechanical cleaning filters.

When turbid suspension appears in the pool, flocculants are used to eliminate it. They glue small particles of pollution and contribute to their precipitation

No. 3 - electrophysical cleaning filters

Electrophysical filters for cleaning swimming pools began to be used quite recently.

Basic methods of electrophysical water purification in swimming pools:

• ozonation;
• ultraviolet radiation;
• silver ionization;
• ionization with copper.

Ozonation is considered one of the most progressive and environmentally friendly methods of purifying pool water. Ozone has powerful oxidizing properties. When it passes through water, almost all bacteria are destroyed, while the composition of the water remains unchanged.

The main advantages of ozonation:

• destruction of bacteria and microorganisms;
• elimination of unpleasant odor;
• saturation of water with oxygen.

The disadvantages of the cleaning system include the need for a special installation and its high cost. When ozonizing water, the ozone concentration should not exceed 0.03 mg/m3; an overdose can be harmful to humans.

Since the effect of ozone on the human body has not been fully studied, ozonation of water is prohibited in a number of countries.

Ultraviolet radiation is another way to effectively purify water, allowing you to completely eliminate chemicals. When purchasing and installing an ultraviolet lamp, you need to take into account that it only works effectively in purified water.

For an ultraviolet lamp to work effectively, the water must be purified as much as possible; therefore, it is recommended to install the lamp directly behind a mechanical filter

When treated with ultraviolet rays, water retains all its beneficial qualities, but the effect is short-lived.

It is recommended to combine the ultraviolet purification method with another reagent, since after the cessation of radiation, microorganisms entering the water multiply intensively.

Today, water ionization is the most advanced cleaning method. Copper and silver ions are released into the water under the action of electrodes to which a weak current is applied. Copper ions prevent the growth of algae, and silver ions completely destroy viruses and bacteria.

During the ionization process, under the influence of a weak current, microscopic particles of copper and silver are split off, providing effective purification of water from impurities, algae, viruses and bacteria

Ionization of water has the following advantages:

• copper and silver ions remain active for a long time;
• when using an ionizer and an ozonizer together, you can avoid chlorination;
• after ionization, the water meets the drinking standard;
• absence of allergic reactions and odor.

In addition, copper ions contribute to the gluing of tiny particles (they perform role of coagulant).

Disadvantages of water purification by ionization:

• poor combination with other disinfection methods;
• the impossibility of completely eliminating chlorination in large pools;
• To date, the influence of metal ions on the human body has not been fully studied.

The combination of ionization and chlorination is most widespread in large pools. You can abandon the chlorinator by replacing it with an ozonator, but the combination of “ozonation - ionization” is used quite rarely due to the high cost of the equipment and significant energy consumption.

No. 4 - combined water filtration systems

Combined cleaning involves the installation of a whole system of filters and devices. When choosing combinations, one should take into account the influence of cleaning methods on each other, the decrease and increase in their effectiveness.

For example, a combination of ultraviolet radiation with the introduction of a solution of sodium hypochlorite, hydrogen peroxide or ozone works well.

Basic steps to implement a comprehensive cleaning system for large swimming pools:

• selection of main and additional pumps;
• installation of mechanical and chemical filters;
• installation of ionization, ozonation, UV;
• selection of heat exchanger;
• preparing premises for pumping equipment;
• complete set and assembly of the system.

It is important when designing a complex filtration system to carry out all the work before installing the pool. Otherwise, the work on laying communications and connecting will become significantly more complicated.

It is also important not to forget when designing to pay attention to the organization of the correct pool ventilation.

A combined filter system requires a significant area and large financial investments, but at the same time provides maximum purification of the pool water

Complex combined water filtration systems are used in large public stationary swimming pools. Only such systems avoid periodic drainage of water and mechanical cleaning of the bottom and walls swimming pool

You may also be interested in information on how to choose pool heat pump or how to choose best robot vacuum cleaner for automatic pool cleaning.

Conclusions and useful video on the topic

Overview of sand filter operating modes:

Disinfection of the pool with submersible ultraviolet lamps:

An effective way to keep your pool water clean:

The choice of a filtration system must be approached very scrupulously, since the health of those who swim in the pool depends on the quality of the water.

If the issue of water purification in a small home pool can be solved by a good mechanical filter pump, then for large structures a whole system of filters and devices will be required.

Healthy: Re-opening the pool after winter.

Have you installed a home pool on your property? Tell us what filter you use to purify water and whether you are satisfied with the result. Have you noticed any inaccuracies or inconsistencies in this article? Write to us about them in the comments block.