Filtration time calculator: how many hours should you run your pool?
The most reliable rule to filter just enough: divide the water temperature by two. Water at 26 °C therefore needs about 13 hours of filtration a day. Enter your temperature to get your duration.
Result
Recommended filtration time13h/day
How this calculation works
This calculation applies the reference rule of pool maintenance:
Daily filtration time (hours) = Water temperature (°C) ÷ 2
The logic is physical: the warmer the water, the faster micro-organisms develop, and the longer filtration must run to keep the water clear. This duration is the total over 24 h; it can be split across the day, ideally during the warmest hours.
Frequently asked questions
Should I filter the pool during the day or at night?
Preferably during the day, at the warmest hours, when the risk of algae growth is highest and treatment works best. Night filtration remains useful during heavy use or a heatwave.
What happens if I filter too little?
Insufficient filtration lets the water go cloudy, encourages algae and makes chemical treatment less effective. When in doubt, filter a little more rather than too little.
Does the temperature ÷ 2 rule apply to every pool?
It is a reliable baseline for a typical family pool. Heavy use, already degraded water or a heatwave justify extending the time beyond this result.