Inflatable hot tub setup and maintenance: a practical guide

Setting up your inflatable hot tub

Start by choosing the right spot: a flat, level, load-bearing surface with room around the edge to climb in and out. A patio or reinforced decking is ideal; soft or sloping ground is not, since a filled tub can weigh well over a tonne. Lay an insulating ground mat first, both to protect the base from cold and sharp stones and to cut heat loss into the ground. Then inflate the tub with the supplied pump, which takes about 10 to 15 minutes from flat and brings the walls up to a firm pressure; do not over-inflate, as the walls should feel firm rather than drum-tight.

Next, fit the pump-heater unit to the tub following the instructions, then fill with a garden hose to the marked fill line, which takes roughly 45 to 90 minutes depending on the tub's volume. Switch the heater on the day before you want to use it, since heating from a cold mains fill of around 15°C takes 16 to 24 hours to reach the maximum 40°C, and keep the lid on the whole time it heats. Plug the unit into an outdoor-rated, RCD-protected socket on its own circuit, in line with the kind of outdoor wiring guidance set out in the IET Wiring Regulations (BS 7671). Finally, once the water is in, add your sanitiser so the tub is safe from the first soak.

The chemicals you actually need

Water care sounds daunting but comes down to a short list. The essential item is a sanitiser, which kills bacteria: most owners use chlorine granules, though bromine tablets are a popular alternative that copes better with the higher temperatures of a hot tub. You also need test strips to read the sanitiser level and the pH at a glance, and pH adjusters (pH increaser and decreaser) to keep the water balanced. A tub with a built-in UVC steriliser, such as the MSpa Comfort Bergen, lets you use less chlorine because the UV light deactivates much of the bacteria, but you still need some sanitiser as a backup.

Useful extras include a floating chemical dispenser to release sanitiser slowly, a foam-reducing additive if you use bath products near the tub, and a no-clog or anti-scale product if you live in a hard water area. Many tubs, including the Intex PureSpa Bubble, come with a hard water treatment cartridge that softens the supply as you fill. Store all chemicals separately, out of reach of children, and never mix them in their concentrated form. Following the dosing instructions on the pack and the hygiene principles set out by bodies such as the Health and Safety Executive keeps the water safe for everyone using it.

Balancing the water

Balanced water is comfortable to soak in, kind to the tub and efficient for the sanitiser to work. Aim for a pH between about 7.2 and 7.6, which is close to the body's own and stops the water feeling harsh or going cloudy. Test the water with a strip after filling and before each use, and adjust the pH up or down in small steps, retesting after the pump has circulated the water for half an hour. Keep the sanitiser within the range your test strips recommend; too little and bacteria thrive, too much and the water smells strongly and can irritate skin and eyes.

Temperature plays a part too. Hot tub water sits at up to 40°C, which is warm enough that sanitiser is used up faster than in a cold pool, so you will dose more often than you might expect, especially after a busy session with several bathers. Check and top up the sanitiser after heavy use, and give the water a few minutes to circulate and disperse the chemicals before anyone gets back in. Getting into a rhythm of testing little and often is far easier than fixing water that has been left to go cloudy or green.

The weekly routine and water changes

A short, regular routine keeps everything running well. Every few days, rinse the filter cartridge under a tap to clear out hair, leaves and debris, and replace it roughly monthly, since a clogged filter makes the pump and heater work harder and pushes up running costs. Skim any floating debris off the surface, keep the water topped up to the fill line so the pump is never starved, and wipe the waterline occasionally to stop a greasy ring building up. Keep the insulating lid on whenever the tub is not in use, both for hygiene and to hold the heat.

As a rule of thumb, drain and refill the tub every one to two weeks with regular use, or sooner if the water looks cloudy or smells off despite correct chemical levels. To change the water, switch off and unplug the heater, attach the drain hose and empty the tub away from plants and drains, give the inside a wipe with a soft cloth, then refill, rebalance and reheat. When you pack the tub away for winter, dry it thoroughly before deflating to prevent mould, and store it somewhere dry. Done consistently, this routine takes only a few minutes a week and keeps the tub clean for years; our buying guide and running costs guide cover the rest of ownership.