Advice · 4 min read · Updated 6 November 2026

7 hot tub myths: chlorine smells, red eyes, hot water and germs

Myth 1: a strong chlorine smell means too much chlorine

The sharp smell people associate with chlorine usually comes from chloramines, which form when chlorine reacts with sweat, skin cells, cosmetics and other contaminants. A strong smell often means the free chlorine has been used up and the water needs topping up or a shock dose. Properly balanced hot tub water has very little smell.

This is why a busy party tub often smells more than a quiet one. The bathers have added more contaminants, and the chlorine has been working hard to deal with them. Testing the free chlorine level will tell you what is going on, and a shock dose as directed by the supplier usually clears the smell.

Myth 2: red, stinging eyes mean too much chlorine

Sore eyes and itchy skin are more often caused by chloramines or by pH that is too high or too low. Test both the sanitiser level and the pH. Many suppliers aim for pH around 7.2 to 7.6. Bringing the pH back into range and keeping sanitiser at the recommended level usually solves the problem.

Myth 3: hot water is too hot for germs

Hot tub temperatures, usually 37 to 40°C, are ideal for many bacteria, not too hot for them. Without a sanitiser, bacteria such as Pseudomonas, which can cause a skin rash known as hot tub folliculitis, and Legionella, which can cause Legionnaires' disease, can grow. That is why sanitiser, filtration and good hygiene are essential.

Warm water also evaporates and uses up sanitiser faster than cold water, and the jets and bubbles can turn water into a fine spray that people breathe in. That is another reason to keep sanitiser levels right and to keep the cover on when the tub is not in use.

Myth 4: household bleach or pool chlorine will do

Household bleach is not designed for hot tubs. It may contain additives, its strength varies and it does not include stabilisers or the right dosing instructions. Swimming pool chemicals can be the wrong type or strength for the small volume of a hot tub. Use only the products and doses the hire supplier provides or recommends.

Myth 5: clear water is clean water

Water can look clear but still have low sanitiser levels, especially after heavy use. Test strips, not appearance, tell you whether the water is safe. Test at least once a day during a hire and more often during and after a party.

The reverse can also be true. Slightly hazy water after a busy session does not always mean the water is unsafe, but it is a sign to test, top up the sanitiser as directed and rinse the filter. If it does not clear within a few hours, contact the supplier.

Myths 6 and 7: covers and showers

Myth 6 is that the cover is optional, and myth 7 is that a shower before getting in makes no difference.

Some people think the cover is only there to keep leaves out. In fact it keeps the heat in, reduces evaporation and chemical loss, and stops children or pets falling in. Keep it on and strapped whenever the tub is not in use.

Others think a quick shower before getting in is optional. Rinsing off sweat, lotion, make-up and deodorant reduces chloramine formation and makes the sanitiser last much longer. It is one of the easiest ways to keep the water fresh.

What actually keeps the water safe

If the water is cloudy, foamy or smells strongly despite following the instructions, stop using the tub and contact the supplier.

A good supplier will explain the test strips, the target ranges and how much of each product to add when they set the tub up. If anything is unclear, ask at delivery rather than guessing later. Keep the instructions somewhere dry near the tub so everyone using it can follow the same routine, and keep all chemicals in their original containers, out of reach of children.

Frequently asked questions

myths chlorine water care hygiene