If you can smell chlorine, the pool has too little of it working, not too much. That smell is chloramine: chlorine that has already reacted with sweat, urine and skin and is now doing nothing useful except irritating eyes and airways. A well-run pool barely smells at all.
Swim school operators are not pool technicians and should not pretend to be. But you stand in the water for hours a day with other people’s children, and you need to know enough to recognise when the water is wrong and to have the confidence to cancel.
What Sanitation Is Actually Doing
Two jobs, constantly. Kill pathogens introduced by bathers, and oxidise the organic material they leave behind. Chlorine, in one form or another, does both in most pools. Bromine is used in some warmer water. Ozone and ultraviolet systems assist but do not replace a residual disinfectant in the water itself, because nothing else protects a swimmer from the swimmer next to them.
Alongside the disinfectant sits pH. Chlorine’s ability to kill things collapses as pH climbs. A pool with plenty of chlorine and a high pH can be effectively unsanitised. This is the most common failure in poorly managed residential pools, and it is invisible.
The Three Signals You Can Read Without a Test Kit
| What you notice | What it usually means | Action |
|---|---|---|
| Strong chlorine smell, stinging eyes | Chloramines. Disinfectant consumed, ventilation poor | Raise it with the operator. Consider cancelling if severe. |
| Cloudy water, drain grate not visible | Filtration or chemistry failure | Do not swim. This is also a rescue hazard. |
| Slippery walls or tiles below the waterline | Biofilm. Insufficient residual disinfectant | Report. Do not run a lesson. |
| Coughing swimmers in an indoor pool | Airborne chloramines, poor air handling | Move the session or shorten it. Asthmatic swimmers first. |
| Green tint | Algae. Chemistry has been out for days | Cancel. |
The clarity test is simple and non-negotiable. Stand at the deep end. If you cannot clearly see the bottom drain, a person on the bottom would not be visible either. That alone ends the lesson.
What Swimmers Bring Into the Pool
- Sweat and skin cells, in large quantities, which consume disinfectant directly.
- Urine, which is the main source of the chloramines that make eyes sting.
- Cosmetics, sunscreen and hair product, which form a surface film and clog filters.
- Faecal contamination, occasionally, which is the one that closes a pool.
A pre-swim shower is not a courtesy. It removes a meaningful fraction of what the chemistry has to deal with. Make it a rule in your school and enforce it with the children, because their parents will follow them.
Common Mistakes Operators Make
- Judging a pool by the chlorine smell, backwards.
- Testing disinfectant without testing pH, which makes the disinfectant reading meaningless.
- Running a lesson in cloudy water because the class was booked and paid for.
- Assuming a condominium pool is tested daily. Many are tested weekly, if that.
- Letting a child with diarrhoea in the previous fortnight into the water.
- Believing a saltwater pool is chlorine-free. It generates chlorine from salt. It is a chlorine pool.
- Ignoring instructor skin and respiratory complaints. Instructors are in the water far longer than swimmers and show problems first.
Asthma, Skin and the Instructor
Poorly ventilated indoor pools with high chloramine levels aggravate airways. Swimmers with asthma should carry their reliever on deck, and their asthma management belongs entirely to their doctor. A coach’s job is to notice the environment is bad and change it, not to advise on medication.
The same applies to instructors. If you are teaching thirty hours a week in an indoor pool and coughing at night, that is the building talking to you. Raise it with the facility and see a doctor.
Questions to Ask Before You Hire a Pool
How often is the water tested, and can you see the log? Who holds the pool operator qualification? What is the turnover rate of the filtration system? What happens when a fouling incident occurs, and how long does the pool stay closed? An operator who answers these easily is running a good pool. One who does not have the log is telling you something.
Frequently Asked Questions
Why does my pool smell of chlorine?
Because of chloramines, formed when chlorine reacts with organic matter from swimmers. It is a sign of spent disinfectant and inadequate ventilation, not of excess chlorine.
Is a saltwater pool better for swimmers?
It produces chlorine electrolytically and many swimmers find the water gentler on skin and eyes. It is still a chlorinated pool and it still needs pH management.
Can I swim in a cloudy pool?
No. Cloudiness means the chemistry or the filtration has failed, and it means a swimmer on the bottom cannot be seen. Both reasons are sufficient on their own.
Does chlorine damage hair and skin?
Prolonged exposure dries both. Rinse before and after swimming, and shower properly afterwards. Skin conditions that worsen with swimming should be discussed with a doctor.
How soon after a stomach bug can a child swim?
Public health guidance generally advises a substantial wait after diarrhoea stops. Ask the venue for their rule and follow it. A single incident can close a pool for a day.
Who is responsible for water quality in a condo pool?
The management corporation and the contractor they hire. As a visiting coach you have no control over it, which is exactly why you need to be able to read the water and walk away.
Walk Away When It Is Wrong
The cost of cancelling a lesson is one refund and an awkward conversation. The cost of running a lesson in water you cannot see through is much higher. Learn the three signals, ask for the log, and hold the line.
Coaches teaching in residential pools face this most often, since supervision and testing standards vary enormously between developments; see local condominium swimming providers. Facility standards and national programme information are available from Sport Singapore.
Explore more guidance in the Swim Schools International Resource Hub, or learn about SSI swim teacher certification.
Water-quality checks are one layer of a wider safe-delivery system. Review the water safety education framework and swim school SOP guide.
