FILTERS FOR SWIMMING POOLS: HOW TO CHOOSE AND TIPS FOR USE

One of the most important components of the pool treatment plant is the filter. It is the main mechanism for cleaning and purifying water, and plays a crucial role in keeping water crystal clear and suitable for bathing residential pool plans. The filter is responsible for removing impurities that, sometimes, we only realize exist when the pool has already lost all its beauty and healthy appearance.

Although there are different types of filters for swimming pools, they all work in the same way: the pool water is sucked through the skimmer and sump thanks to the power supplied by the pump, and passes into a tank or reservoir that contains a special material of filtered out. It then returns to the pool, completing one cycle. Depending on usage, a complete pool water cycle per day is advised.

What we mean by "cycling" is the passage of all the water in the pool through the filter, a process whose duration depends on several factors: the size of the pool (in other words, the amount of water), the pump / motor power, and also the capacity of the filter used. When choosing these components, all these factors must be taken into account, so that the duration of the cycle is not excessive (about 8 hours are recommended for a residential pool).

FILTER TYPES

There are three different types of filters:

Sand filters. Sand filters are by far the most popular, and at the same time, they are also the least maintenance-intensive. Sand is a natural filtering agent used by nature, and this principle is applied to this filtration system. The water is cleaned by passing through a sand tank. The great advantage of this purification mechanism is the durability of the filter, which could last up to ten years, although it is advisable to change after seven. By allowing backwashing, it is also extremely easy to clean.

Cartridge filters. Cartridge filters rely on replaceable cartridges for cleaning, which last approximately one year and must be cleaned weekly. Its operation is similar to diatom filters, except that the filtration is carried out on the basis of manufactured materials. The great advantage is the ease of cleaning and its installation.

Diatom filters. Finally, the diatom filters, the top of the range. Diatoms are fossilized microscopic beings that act as filtering agents, with unprecedented efficiency: they work like micro-sponges, letting water through and containing dirt that is not even visible to the human eye. Unfortunately, this efficiency comes at a cost, and the price of the equipment is higher than previous filtration alternatives. On the other hand, they also allow back-washing, so cleaning is also simple.

WHICH TO CHOOSE?

Differences in quality are not as important as other factors, such as budget, willingness to do regular maintenance, or even what's on offer in your area.

The capacity of the pool and the power of the pump must be taken into account. These elements will then have to be reconciled with the size of the filter, in order to obtain a cycle of a reasonable length. An always important suggestion is to oversize to avoid problems: if you come to the conclusion that a filter with a capacity of 15 m3 / h is necessary, it will be a good idea to choose a model with a higher capacity (the same with the pump, which has that always compensated with the filter).

At the level of efficiency, and other things being equal, diatom filters are the most effective, with a filtration capacity of around 7 microns. Next we would have cartridge filters, with about 20 and, finally, sand filters, with 60. A micron is one millionth of a meter. As a reference, the human eye is only capable of identifying objects up to 35 microns (a grain of salt is approximately 100 microns).

CLEANING AND WASHING

In order for the filter to perform its function correctly, periodic maintenance must be carried out, which in most cases is reduced to washing it. The frequency of this procedure varies depending on the use of the pool, although the best indicator will be if you consider that the water does not seem as clean as before (a sign that the filter needs to be cleaned).

In the case of sand filters, a good indicator that the filter needs to go through the cleaning process is the increase in its pressure (see manometer). Following the manufacturer's instructions, washing the filters should be carried out when the manometers indicate this sealing pressure.

As for the cartridge filters, cleaning is simple: just remove the cartridges and use water jets to remove the dirt that has accumulated.

Sand and diatom filters generally offer backwashing (or backwashing). With the backwash it is possible to invert the direction of water circulation in the filter and, with this, the filtered materials are expelled to the drain. Backwashing is the most effective way to clean pool filters. The frequency will be given by the conditions of the pool, pools surrounded by grass, sand or earth will need more filter cleaning than pools surrounded by concrete or cement.

Backwashing is a simple process:

- Deactivate the pump.

- Maneuver the selector valve to the backwash position.

- Restart the pump.

- Let the water run for a while until it comes out cleaner (see display on the selector valve).

After washing and before putting the filter into operation, it is mandatory to rinse to resettle the sand and evacuate the water that still contains impurities through the drain. After the washing operations it is necessary to proceed to the purge of the air contained in the filters. To facilitate this operation, the filters can be equipped with automatic drains.

In the case of automatic selector valves, the process is even simpler, since they automatically detect that the filter requires washing (monitoring the filter pressure) and activate the process when necessary.

A very good advice that contributes to respecting the environment is to take advantage of the water that is lost during the washing process. The soil acts as an excellent natural fertilizer (as long as the chlorine level is not higher than 3 ppm), so it can even be used to water your garden or lawn.

SOME ADDITIONAL TIPS

- Stop the pump beforehand for any operation carried out with the valves or filters.

- Clean the filters once a week, even in winter.

- Replace the filter material a little earlier than indicated by the manufacturer.

- Always clean the pre-filter, the basket and the rest of the components.