Heavy rain is one of the most common reasons a clear pool turns cloudy or green within days, especially in the wetter parts of the Highlands like Robertson and the escarpment.
Why rain causes trouble
- Rain dilutes your sanitiser and shifts pH and alkalinity.
- Run-off washes in soil, leaves and garden debris that feed algae.
- The pool may overflow, taking chlorine and salt with it.
- Warm, humid weather after a storm helps algae grow fast.
What to do after a big downpour
- Clear the skimmer and pump baskets and skim the surface.
- If the water level is high, lower it to the normal level.
- Run the pump for longer than usual to circulate and filter the water.
- Test the water and correct sanitiser and pH.
- Brush the walls and floor, and vacuum out debris.
If it’s already green
Once algae has taken hold, it usually needs more than a top-up of chlorine. Our green pool clean-up clears the water and works out why it turned, so it’s less likely to happen again. If you’re on a salt system, it’s also worth checking your chlorinator.