Importance of PIPE DIAMETER and PIPE LENGTH for a pond and proper selection of a pond pump ...

Hopefully you have decided to download the free calculator from www.practical-water-gardens.com/freecalculators.htm

By inserting different values for length and diameter you will see amazing impacts upon pump specification.

You might find it difficult to believe but using small diameter pipes (especially long lengths) can reduce your pump flow to a trickle. Pipe diameter has a bigger impact than pipe length in most cases.

Always use the biggest diameter pipe you can and always have the
shortest length,

In future Gazettes we will talk a lot about pumps and pumping
systems because this is the source of live-giving oxygen to your fish and plants as well as your biofilter's bacteria.

In meantime consider following the pond pumps link above where there is a large amount of information on pond pump selection.