How hot tub works?


A hot tub is a real compendium of technology. Hydromassage nozzles, booster, blower, filtration, heating, pumps, understanding how hot tub works, it will allow you to choose the most efficient and economical model to use. 

How hot tub works?

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How hot tub works – water and air circuit

How hot tub works – Under and around the tank, a whole network of pipes ensures the circulation of water and air .

On the most sophisticated hot tubs, you find 2 water circuits and 1 air circuit: 

  • the water and air circuits which supply the massage nozzles (hydro jets and blowers),
  • the filtration circuit which, as its name suggests, filters the water,

The hot tub filtration circuit directs the water from a skimmer which rids the water surface of impurities to the filter . Some hot tubs also have a bottom strainer to suck up debris deposited at the bottom of the tank. In an overflow hot tub, the water arrives in a gutter or buffer tank.

This contaminated water is purified by a filter . Then the clean water passes through a heating system before being reintroduced into the tank.

This water circulation is possible thanks to one or more pumps.

Read Also : How to clean hot tub? 7 steps

How hot tub works – Hydro jets and the blower

How hot tub works, it is the quality of the massage that makes the quality of the hot tub . Currently you find two types of jets in a hot tub : hydro jets and bubbles .

  • hot tub hydro jets . These are the nozzles which, by sending a mixture of hot water and air under pressure, provide massages to specific areas of the body (neck, shoulders, arms, lower back, legs, soles of the feet, etc.).
    They are powered by one or more boosters or massage pumps and a booster . The greater the number of hydro jets, the more powerful the pump(s) must be.
    Their number is less important than their positioning and the quality of the massage they provide: invigorating, relaxing, energizing massage, etc.
  • The hot tub blower. This anglicism designates the bubble pump which supplies small air nozzles placed at the bottom of the seats and the tank. They are pleasant for rest and relaxation . They do not have targeted action like hydro jets.
    It is advisable that the air be heated so as not to cool the water. 

Programming allows you to set up massage cycles for a given duration (20 to 30 minutes).

How hot tub works Diagram

How hot tub works Diagram

How hot tub works Diagram

How hot tub works – Filtration of water

Filtration purifies water contaminated by debris falling into the hot tub but also by hair, dead skin, residue from body creams or makeup brought by users. This purification is all the more essential as the volume of water is small, it is not renewed at each bath and it is hot. Unfiltered and purified, hot tub water quickly becomes a perfect culture medium!

How hot tub works – Different filtration systems can be used:

  • Surface filtration . It is provided by the skimmer which acts as a pre-filter. It can be equipped with a filter sock. To be effective, it must be cleaned very regularly.
    When the skimmer is connected to the circulation pump, it can provide permanent filtration. 
  • Permanent filtration . It requires a pump dedicated to filtration which operates independently of the water circuit for the massage. It filters water 24 hours a day. It is more energy efficient than cycle filtration. Combined with an antibacterial filter, it also limits the use of disinfectant products.
  • Filtration by cycle or by alternation . It must operate for at least 8 to 9 hours spread over 24 hours. This time must be adapted to the number of users of the hot tub , the atmospheric conditions and its location.

The majority of hot tubs are equipped with a cartridge filter. Compact, it has good filtration quality (around 15 microns). The cartridge should be cleaned regularly with a jet of water and a brush. The most sophisticated filters have a nanometres indicating the degree of contamination of the cartridge.

Read Also : How to clear green pool water fast?

It is also possible to install a sand filter.

Filtration must always be supplemented by water purification: chlorine, bromine, ozone, active oxygen, UV. The water quality in your hot tub must be regularly checked and analysed.

How hot tub works – pumps importance

Different pumps ensure the operation of your hot tub :

  • Boosters : depending on the volume of water, the number and power of the hydro jets, between 1 and 4 pumps (booster) are needed to provide the massage function The action of the pumps is supplemented by a booster.
  • The blower  : it is the pump that generates the relaxing bubbles.
  • The circulation or filtration pump  : not very powerful, it ensures the circulation of water in the filtration. The calories it generates are also used to heat the water.

hot tubs that do not have a circulation pump must use one of the booster pumps to provide cycle filtration.  

How hot tub works – Heating water

To be pleasant, the water in a hot tub must be maintained between 32 and 40° (37° being ideal). The best models also offer heating of the air which is sent by the nozzles in order to avoid cooling the water in the tank too much.

The majority of hot tubs have an electric heater (immersion heater). The larger the hot tub, the greater the power of the heater must be (2 to 9 kW). This very simple system can be expensive to use, especially for a hot tub placed outside. Some manufacturers offer the installation of a heat exchanger with a heat pump .


How often should I clean the filters in my hot tub?

Filters should be cleaned every two to four weeks, depending on usage and water conditions.

Can I use regular pool chemicals in my hot tub?

It’s recommended to use chemicals specifically designed for hot tubs to maintain proper water balance.

Do you need to run a pump continuously or can you start and stop it?

pump can run continuously, many hot tubs have programmable controls, allowing users to start and stop it based on their preferences and energy conservation.

What temperature is ideal for a hot tub?

The recommended hot tub temperature is around 100 to 102 degrees Fahrenheit for a comfortable and safe experience.

How long should I stay in a hot tub in one session?

It’s generally advisable to limit hot tub sessions to 15-30 minutes to avoid overheating.

Are there any energy-efficient hot tub options available?

Yes, many manufacturers offer energy-efficient models with advanced insulation and efficient heating systems.


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