How long does it take to clear a green pool?
Most green pools clear in three to seven days. Light green water with working equipment often turns around in a couple of days. Dark green or black-green water with a failed pump, high stabilizer, or a heavy debris load takes longer and sometimes needs a partial drain.
By Rob, Certified Pool and Spa Operator · Updated September 30, 2026
| Starting condition | Typical time |
|---|---|
| Light green, equipment working | 2-3 days |
| Deep green, heavy bloom | 4-7 days |
| Black-green with debris on the floor | A week or more |
| High cyanuric acid blocking chlorine | Longer, needs dilution first |
What slows recovery down
- A filter that is never cleaned during the process
- Pump running only a few hours a day
- pH left high so shock underperforms
- Leaves and organic debris still on the floor
- Stabilizer far above range
Cloudy grey water after the green is gone is normal, that is dead algae working through the filter. Keep circulation running and keep cleaning the filter and it clears.