How to Fix a Green Swimming Pool: Step-by-Step Algae Treatment
- Algae = chlorine ran out
- Brush + heavy shock
- Pump on 24 hours
- Floc and vacuum to waste
On this page
Why Does a Pool Turn Green?
- Chlorine dropped to zero (missed doses, hot sun, heavy use).
- pH too high, so chlorine stopped working.
- Pump not running long enough, or a blocked filter.
- Rain, leaves and dust adding nutrients.
How Green Is It?
| Look | Severity | Expect |
|---|---|---|
| Light green, can see the floor | Mild | 1–2 days |
| Green, cannot see the deep end | Moderate | 2–4 days, repeat shocks |
| Dark green / swampy | Severe | Several days; consider partial drain and refill |
Green Pool Treatment Products
DAYLIFF CHLORINE 90KSh 3,000
DAYLIFF CHLORINE 65KSh 3,625
DAYLIFF ALGICUREKSh 2,100
DAYLIFF FLOCULLANTKSh 1,560
DAYLIFF PH MINUSKSh 1,500
SWIMMING POOL TEST KITKSh 5,000
MICRO SHOCKKSh 3,500| Product | Price |
|---|---|
| DAYLIFF CHLORINE 90 | KSh 3,000 |
| DAYLIFF CHLORINE 65 | KSh 3,625 |
| DAYLIFF ALGICURE | KSh 2,100 |
| DAYLIFF FLOCULLANT | KSh 1,560 |
| DAYLIFF PH MINUS | KSh 1,500 |
| SWIMMING POOL TEST KIT | KSh 5,000 |
| MICRO SHOCK | KSh 3,500 |
Current listed prices incl. VAT (updated 19 October 2026).
Step by Step
- Remove debris with a net; empty skimmer and pump baskets.
- Test pH and bring it down to about 7.2–7.4 with pH minus.
- Brush every surface to break the algae film.
- Shock heavily in the evening with chlorine at the label's algae/green-pool dose, pump running.
- Run the pump 24 hours a day and backwash or clean the filter whenever pressure rises.
- Repeat the shock the next evening if the water is still green; it should turn cloudy blue-grey as algae dies.
- Add algaecide once chlorine is working, as the label directs.
- Clear the cloudiness: add flocculant, turn the pump off overnight so particles settle, then vacuum the floor to waste (not through the filter).
- Re-test and balance before anyone swims.
Keep It From Turning Green Again
- Test at least twice a week and keep chlorine and pH in range (how to balance pool chemicals).
- Shock weekly (how to shock a pool).
- Run the pump long enough every day for the water to pass through the filter.
- Brush weekly, especially corners and steps.
If the pump or filter is undersized, the pool will keep struggling: see the pool pump guide.
Safety: follow the dose on each product label, add chemicals to water (never water to chemicals), never mix chlorine products with acids or with each other, wear gloves and eye protection, and keep everyone out of the pool until free chlorine is back in the normal range.
Frequently asked questions
How do I clear a green pool fast?
Lower pH, brush, shock heavily, run the pump 24 hours, add algaecide, then floc and vacuum to waste.
Why is my pool still green after shocking?
The dose was too low for the algae load, pH was high, or the filter is clogged. Repeat the shock and clean the filter.
Is it safe to swim in a green pool?
No. Wait until the water is clear and chlorine and pH are back in range.
What does flocculant do?
It clumps fine particles so they sink and can be vacuumed out to waste.
Should I drain a green pool?
Only in severe cases; most green pools clear with chemicals and filtration.