Water filters for washing their types, and which one is better

The tap water in our faucets is mostly unfit for drinking. In order not to buy bottled, you can clean what you have to the desired state. One way to install a water filter under the sink. They are usually equipped with a small tap and are easy to install. Their minus is a decent price and the need to replace cartridges. But they purify water well, which corresponds to GOST.

Types of filters for washing

To obtain drinking water at home, there are two types of water filters for washing – flow cartridge and using reverse osmosis technology (reverse osmosis system). These stationary models are outwardly very similar. They consist of several plastic flask-cases in which filter elements are located. The reverse osmosis system has an additional flask with a membrane.

Cartridge and reverse osmosis system – what’s the difference

The main difference between the reverse osmosis system is the use of a special semi-permeable membrane. The whole point of this cleansing is that only water molecules pass through the very small pores of the membrane. Organic and inorganic substances dissolved in it simply do not pass. Everything is delayed, down to bacteria and microbes.

The degree of water purification by reverse osmosis systems is 98–99%. That is, at the output we get almost distilled water, which has neither taste nor smell. Prolonged use of such a liquid leads to the leaching of salts from the body. Therefore, a mineralizer is installed at the output of the reverse osmosis system, in some models it is immediately included in the package. This is an additional flask in which there is a backfill of useful minerals. It enriches the composition of water, brings it to the norm.

When using stationary flow cartridge filters for washing, you will not get so clean water. Reverse osmosis removes salts, and flow filters (and jugs too) remove them partially. The difference is clear and palpable. In addition, scale remains in the kettle after the flow filter, but it has a different character, becomes looser and can be easily removed.

When using cartridge filters, it cannot be said that purification is bad (about 70–80% versus 95–98% for reverse osmosis), but without a bacterial purification stage (there are such filter elements with silver additives), drinking it without boiling can be risky.

Features of operation

In fact, cartridge systems and reverse osmosis systems are multi-stage filters, which involves the regular replacement of filter elements. Each such element has a certain resource, which is usually indicated in liters, this is how much water it can process without losing quality. Or often they indicate in parallel the time interval of six months, a year, etc. That is, even if the filter has not worked out its resource, it must be changed. It’s just that microorganisms accumulate in them, which, if the deadlines are violated, can enter the water in large quantities.

There is another situation, water deteriorates in quality even before the specified time interval and resource. This happens at an increased level of pollution and the filter runs out of its resource much faster. There are two ways out: to change the filter elements as they get dirty or to put an additional cleaning stage before the installation that solves this problem.

Features of choice

The cartridge system is good in that you can select filter elements depending on the composition of the water (we are talking about both systems). Therefore, before buying, it makes sense to do a water analysis, and then select the composition of the filters in order to purposefully remove the existing problem. For example, reverse osmosis systems do not work well on water with a high iron content. If you have such a problem, iron removal equipment (aeration units or catalytic filters) must be installed before installation, and only after them can reverse osmosis filters be connected.

The second point: for the normal operation of reverse osmosis, decent pressure is required. Depending on the type of membrane, 1,5 atm (50G) or at least 3 atm (100G) is required. If there is no such pressure in your water supply, you must either take the installation with a pump (expensive and few), or put a pump in the system that increases the pressure.

Reverse osmosis is connected to the sewer. There he drains the concentrate of salts, which are removed from the water. If you are planning an installation in a private home and you have a drain pit or storage tank, you need to keep this in mind. A decent amount goes into the sewer, for each liter of purified water, 2-4 liters of concentrate are drained (depending on hardness). A multi-stage cartridge filter is connected only to the water supply, and all the salts removed by it remain in the filters.

Since reverse osmosis removes almost all salts, with prolonged use of such water, salts are excreted from the body. To solve this problem, a mineralizer is placed at the filter outlet – this is a flask filled with mineral salts. It can go in the assembly, or you can put it after the filter. I just have to say that drinking water without mineralization is more pleasant than “salted”, the taste of dishes on such water is also better. Therefore, many manufacturers provide two modes of operation – with or without a mineralizer (switched by a tap).

Here is all the information that can somehow influence your choice between a multi-stage purification filter and reverse osmosis. To say specifically that these water filters installed in the kitchen are good, but these are not, none of the experts will say. Everyone has their own point of view, and everyone has their own version. And each system has its advantages.

Multi-stage cartridge filters

The cartridge itself consists of a housing and a filter element. What contaminants are cleaned depends on the filter element. Water moves like this:

The principle of operation of the cartridge:

• enters the inlet pipe;
• spreads between the wall of the flask and the cartridge;
• passing through the material of the cartridge, it is cleaned;
• rises along the cavity of the filter element;
• comes out of the second pipe.

In multi-stage filters for drinking water, this transformation occurs sequentially in each of the flasks. To make this possible, they are all united by a common element located in the upper part and connecting the individual housings into a single treatment system.

A multi-stage flow-through water filter operates at any pressure that can provide water movement. Flasks are usually made of plastic, it may or may not be transparent. Stainless steel cases are sometimes found, but they are expensive and there are not very many of them.

Parameters and specifications

The main indicators are performance, service life, and non-critical ones – pressure loss, maximum operating temperature. Most often, when choosing a water filter for an apartment, pay attention to the service life. We have already mentioned it above.

Second, performance. This is the amount of water that the unit can purify in a certain period of time. Liters per minute (L/min) is usually indicated, but may be per hour or per day.

Next, you need to pay attention to the size of the filter. There are two standard sizes:

• Big Blue (BB) (in Russian Big Blue) – diameter 185 mm.
• Slim Line (SL) (SlimLine in Russian sound) – diameter 120–130 mm.

Larger format filters are most common, and it is advisable to take them, there will be no problems with replacing cartridges. There are cases of individual sizes, but the difficulty here is that in this case you will be tied to spare parts of only one company, while standard filter elements can be taken from other manufacturers. True, the “head” does not always fit the lid, but there are adapters for these cases.

There are different cases in height. The most common sizes are 10 and 20 inches. If space permits, it is better to take large ones. The resource will be increased and it is necessary to change cartridges less often. But in general, when choosing sizes, you need to be guided by needs, for one or two people a small filter is quite enough.

What are the filter elements

A lot of organic and inorganic substances are dissolved in water, in addition, mechanical impurities are present in the form of a suspension – sand, rust, pieces of winding, etc. In order to get normal drinking water, they must be removed and the content brought to normal. For this, different filter elements are used – cartridges. They are of several types:

• Polypropylene. In multi-stage cleaning systems put first. Their task is to remove mechanical impurities. Pollution accumulates on the surface and in the thickness of the material.
• Coal. Contains activated carbon. Remove chlorine and its compounds, cope well with organic compounds, remove odors. In such cartridges, ordinary activated carbon made from coconut shells (granulated or pressed). Depending on the type of coal, the cleaning efficiency changes (the best is coconut).
• Ion exchange. These cartridges contain ion exchange resins. They do an excellent job of softening water, magnesium and calcium salts (hardness salts) are replaced by sodium. Their disadvantage is periodic regeneration, restoration of working capacity. You can track the time by the appearance of scale in the kettle.
• Combined. They are rarely used in multi-stage systems, the main use is in single-flask versions. It contains several types of filter elements. The quality of cleaning is worse, but if it is necessary to slightly improve several water indicators at once (a little they do not fit into the norm), such options can also be used.

Cartridges have their own options. In addition to the list of contaminants that it removes and physical dimensions, they also indicate a resource – the number of liters of water that this element can purify. It is usually indicated in liters, but often they also put a temporary resource, no more than 3 months, for example.

Popular models of cartridge filters

Most often, filters installed under the sink are three-flask (three-stage), less often there are models with four housings. In any case, the mechanical filter is placed first, then the ion exchange and the last coal. If there are four elements, two coal ones are placed, but with different types of backfill. Sometimes at the fourth stage they put biosecurity, a new generation of filters with silver for disinfection.

The most popular brands are Aquaphor, Geyser, Barrier, products under the Atoll brand showed themselves well. Select the system primarily for water hardness, it is divided into normal, hard, very hard. If there are other problems, such as the need for bacterial cleaning, look for models that can give you such a cleaning. Then look at performance and dimensions.

It is impossible to say that any of these manufacturers is better, they all have an approximately equal number of positive and negative reviews. Barrier filter manufacturers have a very poorly developed after-sales service, although the products themselves are not bad. This is not to say that the Geyser is perfect in this regard, but things are a little better. In general, Russian manufacturers cannot yet please with high-quality after-sales service, so you will have to deal with all the problems on your own.

Another tip that may come in handy when choosing a filter, look not only at the cost of the kit. Much more important is the cost of consumables (cartridges) and their standard sizes, connection methods. Ease of maintenance is also important, filters will have to be changed, so easy replacement is a plus.

Reverse Osmosis Systems

Under the sink in the kitchen, you can put multi-stage water purification filters operating on the principle of reverse osmosis. They are ideal if the water has too large deviations from the norm. When installing a conventional multi-stage filter, it is very difficult to achieve the required water quality; most likely, several more single installations will need to be added to the system, which will make it possible to achieve normal quality water. Reverse osmosis in any case copes with the task, the difference is simply in the amount of water that will merge with the removed salts into the sewer (the harder and more polluted water, the more concentrate is drained).

Principle of operation

The reverse osmosis system consists of membranes with very small pore sizes. Almost all substances in water, including microorganisms, bacteria and microflora, have molecular sizes larger than those of water molecules. And the pores in the membrane are so small that only water passes through them. There are very few foreign substances penetrating the membrane – no more than 0,5-2% of the total amount of water.

On the other hand, all salts remain on the membrane surface. So that they do not pollute it, they are diverted by a stream of water into the sewer.

Features of operation

The size of the membrane for the cartridge is standard. Only the specific characteristics of the membranes are added. They are of two types in terms of performance:

• 50G with a capacity of up to 196 l / day (about 130 ml / min);
• 100G – water purification rate of about 400 l / day (280 ml / min).

The first type of membranes is cheaper, the second is more expensive. To ensure their operation, a certain pressure is required, for 50G it is necessary at least 1,5 atm, for 100G at least 3 atm. If there is no such pressure in the system, you can find an installation with a built-in pump, you can install it yourself, choosing it according to the system parameters.

One more thing: reverse osmosis water filters do not like too chlorinated or ferrous water. In principle, there are pre-filters in front of the membrane that eliminate this problem, but pay attention to what type of water this system is intended for.

Another nuance: such treatment plants work rather slowly, a glass or half per minute, this is not much. Therefore, often in the kit there is a tank for storing purified water. This is not just a container, but a membrane-type tank that maintains a certain pressure inside. Therefore, purified water can be used even when there is no pressure in the water supply. Just remember that the specifications indicate the total volume of the tank. In reality, the water supply in it is about 2 times less.

Some popular models

Since the systems are very similar, they are produced by the same companies as conventional cartridge water purification and softening systems, so new names are rare. In descending order of popularity: Geyser, Aquaphor, Atoll, Barrier. The characteristics of some models are summarized in the table. From it you can get a general idea of ​​​​the order of prices and the difference in characteristics, but each of the models usually has several modifications, as a rule, for water of different hardness or with various additional problems (high iron content, bacterial contamination, etc.).

What else you need to know about reverse osmosis systems, they must be operated constantly. Long breaks are highly undesirable.