Maintaining an inflatable spa: the weekly routine, from cartridges to draining

An inflatable spa can be set up in an afternoon, and that's precisely what catches many users out: you fill it, heat it, enjoy it… then, after a few weeks, the water becomes cloudy, foams when the bubbles start, and gives off an unpleasant smell. There's nothing abnormal about it: a spa is a small volume of hot water shared by several people, the ideal environment for bacteria. Maintaining an inflatable spa comes down to a short but regular routine: shower before bathing, check disinfectant and pH several times a week, rinse the cartridge every two or three days, always keep the cover closed, and completely drain it at regular intervals. Here's how to organize it without spending more than a few minutes a day.

Why a spa deteriorates faster than a swimming pool

Compared to a swimming pool, an inflatable spa concentrates all the factors that degrade the water. The volume is small, often around one cubic meter. The temperature, close to 37 to 40 °C, accelerates the multiplication of bacteria and the consumption of disinfectant. And each bather contributes, relative to the volume, much more sweat, dead skin, cosmetics, and soap residue than they would in a swimming pool.

Result: a perfectly dosed sanitizer on Monday may be almost depleted after an evening with four people. The pH quickly drifts, greasy residues build up along the waterline and in the cartridge, and foam appears. In a spa, the water does not get dirty on its own: it is mainly the bathers who load it with contaminants, and the maintenance routine must match usage.

The right approach is therefore to consider usage: a spa used once a week by two people does not require the same routine as a spa used every evening by a family.

Water settings to know

The values below are common guidelines for a spa; your model's manual and that of your sanitizer remain the reference.

Always start with alkalinity, then pH, then sanitizer: an incorrectly adjusted pH makes chlorine much less effective. To dose correctly, you also need to know your spa's exact volume; if it is not indicated, our method for calculating the volume of a round pool works very well for a round spa.

The routine: every day, every week, every month

With each use

• Shower without soap before getting in, tie your hair back, and avoid cream and makeup. This is the most effective step in the entire routine.
• Swimsuits rinsed with clean water, with no detergent residue: detergent is a common cause of foam.
• Cover it again as soon as you get out, to retain heat and prevent leaves, insects and dust from getting in.

Two to three times a week

• Measure the disinfectant and pH, and adjust them if necessary. After a gathering with several people, a check the next day is essential.
• Rinse the cartridge every two or three days of use (see below).

Every week

• Wipe the waterline with a soft sponge to remove the greasy film before it hardens.
• Carry out a shock treatment if your range of products calls for it, especially after intensive use.
• Check the alkalinity and check the water level.
• Clean the inside of the cover and leave it to dry in the sun for a few hours if possible.

Every few weeks

• Replace the cartridge according to the manufacturer's recommendation and its actual condition.
• Empty the spa completely, clean the wall and refill it with fresh water, according to how frequently it is used.

The filter cartridge, the cornerstone of maintenance

Most inflatable spas filter the water through one or two pleated paper cartridges. They trap particles, body hair, hair and some greasy residue. A clogged cartridge reduces flow, makes the heater work harder and leaves the water cloudy.

1. Turn off the spa's power before removing the cartridge.
2. Rinse with a gentle water jet, from top to bottom, spreading the folds apart to dislodge dirt. Do not use a pressure washer, which tears the paper.
3. Never use soap or washing-up liquid: the residues return to the water and make it foam.
4. For a greasy cartridge, soaking it in a cleaner designed for spa filters, followed by thorough rinsing, will often give it a second life.
5. Having a spare cartridge allows the first one to dry completely, which helps eliminate biofilm.

A cartridge whose folds remain grey or brown after washing, or that collapses or tears, should be replaced. Saving on this consumable often means spending more on chemicals and water changes.

Foam, cloudy water, odours: common problems

The water foams when the bubbles start: this is almost always caused by soap, shampoo, cream, or laundry detergent residue. A spa-specific defoamer calms the symptom, but only prevention (showering, rinsed swimsuits) and draining address the cause.

The water is cloudy: first check the pH and sanitizer, then the condition of the cartridge. Cloudy water despite correct readings often indicates a saturated cartridge or water that is too heavily loaded and should be replaced.

The water smells strongly of chlorine: paradoxically, this is often a sign of insufficient active chlorine. The smell comes from chloramines, formed when chlorine reacts with sweat and urine. Shock treatment and good ventilation, with the cover open for a few hours, improve the situation.

The water turns green: the sanitizer level was too low for several days. In such a small volume, the simplest solution is often to drain, clean, and refill. For green water in a larger pool, the article suggested below explains what to do.

Complete draining without damaging the spa

Even with perfect water balance, spa water accumulates dissolved substances that neither the filter nor the sanitizer removes. After a while, it becomes harder to balance, foams more easily, and uses more products. This is the signal to drain it.

1. Turn off the power and remove the cartridge or cartridges.
2. Drain through the drain plug, directing the water toward a suitable drain rather than onto a lawn or flower bed, especially if the sanitizer level is still high.
3. Clean the walls with a soft sponge and clean water, paying particular attention to the waterline and the nooks around the jets. Avoid household cleaning products.
4. Rinse and sponge the bottom to avoid leaving residue.
5. Fill, put in a clean cartridge, then rebalance the water in this order: alkalinity, pH, sanitizer.

Fill water with a high lime content will encourage deposits on the walls and in the heater: in a hard-water region, pay particular attention to hardness and pH after each refill.

The cover, liner, and minor repairs

The insulating cover is the spa's best ally: it retains heat, limits evaporation, and protects the water from debris. However, its warm, damp inner surface is also a favorable environment for mold. Clean it regularly with clean water, let it dry when weather permits, and check that its straps close securely, especially in strong winds.

As for the structure, inspect the walls and valves from time to time. A spa losing a little pressure is normal when the temperature changes; a rapid loss indicates an air leak. Most models come with a repair kit: clean and dry the area, apply the patch according to the instructions, and let it dry for the specified time before reinflating. Always place the spa on a flat, clean surface free of stones, with the supplied ground mat: this is the best prevention against punctures.

Storing the spa for winter

If your model's manual advises against use in freezing weather, winterizing must be done carefully; otherwise, you may find a moldy spa or damaged pump in spring.

• Drain the spa completely, including any water remaining in the filtration and heating unit, following the manufacturer's procedure.
• Clean and dry thoroughly the wall, cover, and accessories. Residual moisture is the main cause of mold during storage.
• Fold it without creating sharp bends and store it in a dry, frost-free place, away from rodents.
• Discard or replace the worn cartridge: starting the season with a new cartridge is the best way to begin.

In spring, getting it back into service is similar to a first installation: inflating, filling, balancing the water, and gradually raising the temperature. For an above-ground pool coming out of winter, our article on cleaning an above-ground pool after winter follows the same logic on a larger scale.

Read also

If the water has already turned green: How to treat green pool water?.

READ THE ARTICLE

Frequently asked questions

— How often should the water in an inflatable spa be changed?

There is no single rule: depending on usage and maintenance quality, a complete drain every few weeks to three months is a common guideline. Water that remains cloudy or foamy despite a good chemical balance is a sign that it is time to replace it.

— Why is the water in my inflatable spa foaming?

Most often due to soap, shampoo, cream or laundry detergent residue from swimsuits, which accumulates in a small volume of hot water. A soap-free shower before bathing, thoroughly rinsed swimsuits and regular draining solve the problem in the long term.

— Should an inflatable spa be left on all the time?

During the usage season, filtration should run every day according to the manufacturer's recommendations. The heater can be set to a lower standby temperature between uses, with the cover closed, which limits consumption without allowing the water to stagnate.

— Can an inflatable spa be used in winter?

It depends on the model: some are designed to operate in cold weather, but many are not. Check the manual; if it advises against use in freezing conditions, drain, dry completely and store the spa in a frost-free place.

In summary

• Shower before bathing, swimsuits rinsed thoroughly: this is the basis for water that does not foam.
• Disinfectant and pH checked several times a week, with pH around 7.2 to 7.6.
• Cartridge rinsed every two or three days of use, replaced regularly, never washed with soap.
• Cover closed when not in use, cleaned and dried regularly.
• Complete draining at regular intervals and careful winterization: spa drained, dry and stored in a frost-free place.

Last updated: October 3, 2026.