Pool water recirculation: what it is used for, which scheme to adopt and which pump to choose.

The water recirculation pumps and sand filters, together with chlorine and anti-algae products, ensure the constant cleanliness of pool water.

  • Pool water purification is referred to as a filter system: the water recirculation pump and filter work in synergy to ensure safe bathing.
  • The water recirculation schemes differ depending on the type of pool.
  • Pool water recirculation pumps must be correctly sized to ensure adequate filtration.

A nice dip in the pool, but only if the water is clear and safe. How to do this? You need proper filtration and efficient technology, starting with the choice of the most suitable recirculation pumpProper pool hygiene certainly requires treatment of a chemical nature. Chlorine or salt chlorinator are one of the most effective methods of sterilising water, used in the appropriate quantity that must be calibrated according to water temperature, number of swimmers and exposure to the sun.

pompe per il ricircolo acqua in piscina | Water Fitters

It is also important to distinguish between
- shock treatment: is usually carried out before the pool reopens after the winter break, or in the event of particular conditions that may alter the chemical balance of the water;
- daily routine: i.e. the disinfection that is regularly carried out while the pool is in use and which allows ideal pH values to be maintained.
Chemical treatment therefore takes care of the elimination of all microbiological and organic contaminants and the maintenance of the water's mineral balance, but it is not enough. There is also a need for mechanical treatment, which is fundamental in the filtration and circulation of water.

Pool water recirculation: skimmer or overflow?

The pool water recirculation pump is the heart of the system. However, before analysing the characteristics of swimming pool pumps, let us see what pool water recirculation is for and how it can be achieved. First of all, it is necessary to remove all impurities that are in suspension or dissolved, thus ensuring that the water in our swimming pool is always clear and crystal-clear.Going into more detail, we can distinguish between two treatment methods or recirculation schemes for swimming pool water.

schema di un circuito per il ricircola dell'acqua in piscina | Water Fitters
The skimmer recirculation scheme is used for in-ground pools where the water level is about ten centimetres lower than the edge. The skimmers are nothing more than openings placed along the upper edge of the pool which, together with the bottom outlet, allow the water to be sucked in and returned after filtration. Naturally, the number of skimmers must be adapted to the size of the pool to allow effective recirculation. In the case of overflow pools, where the water is flush with the edge of the pool, the recirculation scheme instead involves a system of overflow channels where the water is conveyed and then passes into a compensation tank. The channels, covered by a walkable grid, are placed along the perimeter of the pool for a length corresponding to at least 60% of the total perimeter.
From the compensation tank, which must be dimensioned to take volume variations into account, the water is sucked in, fed into the filtration system and eventually fed back into the pool through the bottom outlets. To prevent the water from flowing back into the compensation tank when the system is stopped, non-return or check valves should be installed.
This recirculation scheme also applies to infinity pools, the impressive infinity overflow pools that give the observer the impression that the water disappears over the horizon. The only difference, compared to normal infinity pools, is that the water, once filtered, is fed into the pool through nozzles not at the bottom but at the wall.

Swimming pool water recirculation pumps: the heart of the filtration system.

Filtering swimming pool water means passing it through devices capable of retaining impurities. It is important to choose the most suitable filtration materials and, of course, to go for quality products. However, in order to fulfil their function, hydraulic filters require sufficient recirculation and therefore a suitably sized pump. As always, one must consider flow rate and head, but above all filtration speed, on which the time required to complete two complete filtration cycles of our pool water depends.

How is the filtration time calculated?

First of all, the volume of water to be filtered must be considered, and then it must be related to the flow rate of the pump, i.e. the quality of liquid it can move in the unit of time. The lower the capacity of the pool pump, the longer the time required for filtration. The ratio between flow rate and capacity must be multiplied by two because, as mentioned above, two are the filtration cycles that must be expected in 24 hours.
In addition to correct sizing, it is important to choose pool pumps that are reliable, safe and silent. Not only that, having to operate for several hours, the choice of energy-efficient pool water recirculation pumps can be very strategic. When talking about swimming pool pumps, we must also not forget the importance of maintenance, which not only extends the life of the system but also ensures its efficiency.
Finally, a detail concerns the characteristics of the water. If salt is used as a disinfectant instead of chlorine, or if our pool is filled with sea water, we must check that the pump chosen is compatible with salt water.