Different pond centrifugal pumps perform different tasks, which is why there are so many.Opt for a pond pump which circulates your required water volume at least every 2 hours, but do not choose a pump too much more powerful than you need if you want to save on power consumption. Your fountain should not reach over half your ponds narrowest point to avoid water splashing around the pond in windy conditions. It is always advisable to buy the largest diameter flexible hose to connect your filter.5 x 1000, so 4500 litre water volume. Filter pumps are sometimes called solids-handling pumps because they move solid waste to a pond filter, and are therefore ideal for keeping ponds clean. The oasis of calm which a pond offers is unrivalled by any other garden feature.5 metres, you have 4. You may also want to compare the power consumption of various pumps and only buy one which comes with a guarantee for peace-of-mind. Online retailers offer a wide range of products and are able to offer help and advice by phone to help you choose the right filtration system for you.For fountain displays, you will need to calculate the volume of water in the same way. Your pond pump will come with instructions for installation.