What size pond pump or filter do you need?
It is recommended that your entire pond water volume should be circulated through the filtration system every two hours.
So that means you need a filter that can process half of your pond volume in one hour.
Here’s an example.
Pond volume = 5,000 litres
5,000 / 2 = 2,500 litres per hour.
It is advised that you round up to ensure that the required level of filtration is met. In this example you’d chose a filter and pump that can handle 3,000 litres per hour.