What does your water look like?
Your pool is green because algae is growing, almost always because free chlorine dropped too low. Cloudy water usually means low chlorine, high pH or a tired filter. Brown or rust-coloured water means metals such as iron, often from well water. Each fix is below, with the point where a service visit saves you money.
Why is my pool green?
Algae. Free chlorine dropped too low, usually after hot weather, heavy rain, a pool party or the pump being off.
- Test free chlorine and pH. Bring pH to 7.2 to 7.6 first, because chlorine works poorly at high pH.
- Brush the walls, steps and floor, then shock the pool well above your normal chlorine level and keep it there.
- Run the filter 24 hours a day and clean or backwash it daily until you can see the floor.
Book a visit if you still cannot see the floor after 48 hours, or the water is dark green.
Why is my pool cloudy or milky?
Usually low chlorine, high pH or alkalinity, or a filter that is not keeping up. Very common in the first week after opening.
- Test pH, alkalinity and chlorine, and bring pH to 7.2 to 7.6.
- Raise chlorine to your normal level and run the filter around the clock.
- Backwash or clean the filter. Old sand or a worn cartridge may need replacing.
Book a visit if it stays cloudy after three days of good readings. The filter is the usual cause.
Why is my pool water brown?
Metals, usually iron from well water or corroding parts. Shocking brings the metal out of the water and can stain the liner.
- Stop adding shock until you know what it is.
- Test for iron and copper. Common with well water around Napanee and Prince Edward County.
- Add a metal sequestrant, run the filter and clean it. Fill with trucked water next time if your well is high in iron.
Book a visit if the liner is already stained. Some stains lift with the right treatment and some do not.
Why is my pool foamy?
Too much algaecide, or a build-up of sunscreen, lotion and other body products.
- Run the filter and give it a few days. Foam from algaecide fades on its own.
- Shock the pool to break down oils and lotions.
- Ask swimmers to rinse off before getting in.
Book a visit if foam keeps coming back. It usually points to a dosing problem.
Why does my pool smell like chlorine?
Not too much chlorine but too little. The smell comes from used-up chlorine, called chloramines, which shock breaks down.
- Test free and total chlorine. A gap of more than 0.5 ppm means chloramines.
- Shock the pool in the evening and run the filter overnight.
- Leave the cover off for a few hours afterwards so the gases escape.
Book a visit if the smell keeps returning. Weekly maintenance stops the build-up.
Quick reference: water colour, cause and fix
| What you see | Likely cause | First step | How urgent |
|---|---|---|---|
| Green | Algae from low chlorine | Balance pH, brush, shock | Today |
| Cloudy or milky | Low chlorine, high pH, filter | Test and run the filter 24 hours | This week |
| Brown or rust | Iron or copper | Stop shocking, test for metals | Before it stains |
| Foamy | Algaecide or body products | Wait, then shock | Not urgent |
| Chlorine smell | Chloramines | Shock in the evening | This week |
Safe swimming water guidance comes from Health Canada's recreational water guidance. Tired of chasing it? Weekly pool maintenance keeps water balanced, and a green pool at opening is covered by our pool opening service.
Questions about why is my pool green
How long does it take to clear a green pool?
A light green pool usually clears in two to four days with steady high chlorine, brushing and constant filtering. A dark green pool can take a week and often needs a filter clean partway through.
Should I drain a green pool?
Almost never. Draining a vinyl liner pool can shift or damage the liner, and the algae can be cleared with chlorine and filtering.
Why is my pool cloudy after shocking?
Shock kills algae, and the dead algae makes the water cloudy until the filter catches it. Keep the filter running and clean it once the pressure rises.
Can well water turn my pool brown?
Yes. Iron in well water turns brown or rust-coloured when chlorine is added. Test for metals and use a sequestrant before shocking.
Last updated by the Limitless Pools service team. Questions? Contact us.
