Flow Calculators

This page contains two calculators to help you select the right size pump. The calculators will calculate the flow required, you can then choose a pump which can deliver this flow at the head required. The head is the maximum height, measured from the surface of the pond, to which the water will be pumped. It is not measured from the top of the pump.

These calculators assume that the waterfall / filter is close to the pond. Very long pipe runs will require a more powerful pump.

The first calculator is for use when you want a waterfall of a particular size. The second calculator is for calculating the flow required to filter your pond if you have fish. After the water has passed through the filter it can be returned to the pond via a waterfall, if desired. The calculator shows the approximate width of the waterfall that would be supplied. Remember that if the waterfall is higher than the filter it will increase the head requirement.