What treatment should I choose for the water in an inflatable spa?


Ideal for relaxing with family or friends, the inflatable spa is an alternative that has become accessible to many homes. Installed indoors, on the terrace, the balcony or even in a garden shed dedicated to this relaxation area, the spa must be maintained regularly in order to preserve the purity of its water.

Inflatable Spa Specifications

The advantage of the inflatable spa is that it can be moved at will, is lightweight and accessible with a much smaller budget than would be required for a ‘hard’ spa. However, the PVC of which it is made does not allow the use of all the usual treatment products, which could damage it or weaken its walls. The heat of the water is another concern, as is its possible positioning in full sunlight. In order to maintain it and keep the water clean and clear, the treatment products must be chosen with discernment.

What are the best treatment solutions for the water in an inflatable spa?

Bromine, salt, active oxygen… There are many solutions for treating the water in an inflatable spa.


For optimal disinfection, bromine is undoubtedly the most suitable product for spa water because it tolerates high water temperatures and is not sensitive to UV light in the case of a spa used outdoors. Best of all, it is effective even at high pH levels. It is odourless and is not harmful to the skin and mucous membranes.

Easy to use, it comes in the form of tablets to be inserted into the filter cartridge housing. Count 60 g of bromine per cubic meter of water, it will thus be disinfected for about a week, just test if the quantity of bromine is still between 3 to 5 mg/l in order to add tablets as needed.

Special swimming pool salt

If your spa is equipped with an eco-sterilizer, you will be able to treat the water with salt.

Salt water chlorination is gentle on mucous membranes and skin, odourless and inexpensive. Salt water chlorination is both effective and convenient, however the pH should be maintained between 7 and 7.6. Regular pH analyses should therefore be carried out before each treatment in order to adjust this parameter using specific products (pH+ or pH -).

After passing through the filter, the salt is led to the electro-sterilizer whose cell will cause a chemical electrolysis reaction transforming the salt into sodium hypochlorite. The water is thus disinfected.

Be careful to follow the manufacturer’s instructions regarding salt dosage, as the cell of the appliance could be damaged if the dosage is too low.

If your spa is used regularly, set the treatment time to 8 hours each day. This time can of course be adjusted if your spa is not visited daily!

Active oxygen

Active oxygen is odorless. It is very gentle to the skin and mucous membranes, is ideal for sensitive people and does not damage the hair.

Very easy to use, simply pour the active oxygen granules directly into the spa water before each use. A dosage of 10 to 20 g of granules per cubic metre of water is usually sufficient, however, this dosage should be modulated in case of high water temperature.

However, this treatment is sensitive to many parameters and should preferably be used in a stable environment.

It is not recommended for a spa placed in full sunlight as the action of UV light greatly reduces its effectiveness. The same applies to temperature variations (high amplitudes). It is preferable to choose an indoor spa or a spa sheltered from these unfavourable climatic conditions. An active oxygen activator will be particularly recommended in an unstable environment, with water heated only occasionally, or in the event of untimely pH variations. This product is in the form of a liquid that will be added to the spa water once a week.

Active oxygen reacts poorly to pH changes, so it is imperative that the pH be between 7 and 7.6 for the treatment to be most effective. A daily monitoring of the pH level by means of specific strip tests is highly recommended!

If the water is warm, simply add an oxygen activator and increase the amount of active oxygen.

Active oxygen is environmentally friendly, it does not pollute the water with chemical compounds, so the water can be recycled in the garden.

Chlorine: a common mistake

Chlorine is not suitable for treating the water in an inflatable spa, although specific kits are available. Attractive because it is cheap, it is slightly corrosive to PVC which is a first brake. Its very characteristic smell doesn’t really fit with the Zen atmosphere and the notion of relaxation that a spa session should inspire.

If the pH of the water is high, chlorine will have little effect. To be fully active, chlorine must be used in water with a pH between 7.2 and 7.4. Above a pH of 8 or higher, it loses almost all its effectiveness.

If your spa is placed in the sun, UV rays will degrade the chlorine and make it ineffective.

If the water temperature is above 28°C, which is usually the case in a spa, the chlorine will once again be inactive.

Chlorine, despite its availability and low cost, is therefore not the preferred solution for an inflatable spa.

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