Pool smells strongly of chlorine: too much or too little?
A strong chlorine smell and stinging eyes almost always mean too little chlorine, not too much. Understand why and how to fix it.
2 min read
It sounds odd, but that strong "pool smell" almost never comes from too much chlorine. It comes from chloramines: what forms when chlorine reacts with sweat, urine, sunscreen and other dirt. Well-treated water barely smells at all.
How to confirm it
- Kits that measure free and total chlorine (DPD) show the difference: if total is more than 0.5 ppm above free, chloramines have built up.
- Simpler kits (OTO) only measure total chlorine and can't tell the two apart.
- Stinging eyes can also mean the pH is out of range (below 7.2 or above 7.8). Test the pH.
Exception: if the smell appeared right after adding a big dose, it really can be too much. Test before adding more, and keep out of the pool until chlorine is back to 3 ppm or less.
How to fix it
Bring the pH to between 7.2 and 7.6.
Shock the pool: it breaks down chloramines.
Keep the filter running and, in an indoor pool, open doors and windows for ventilation.
Test again the next day.
How to prevent it
- Ask everyone to shower before getting in.
- Take children to the bathroom often.
- Keep free chlorine in the ideal range every day, not just on weekends.
The right dose depends on the size of your pool and the product you have. The calculator works it out in spoons and cups.
Calculate the dose now