Pumps need regular attention during the Koi keeping season and need to be removed for annual servicing. External pumps need less maintenance than submersibles, but only if they're installed and housed correctly. It's essential to house the pump in somewhere cool and dry with good air circulation.

Keep filter chambers clean to avoid over working the pump, and your pump will last longer in a clean pond because wear and tear on the seal will be reduced. You may have to send your pump off for maintenance, because the seal keeping the motor dry is usually replaced by the manufacturer. With this in mind it's worth having spare parts.

Submersible pumps are clipped together for easy cleaning and servicing. The bearings will wear down due to debris and limescale, so they need replacing annually. If you live in a hard water area you can save wear on your pump by adding a water softener to a self-contained water feature. If you keep Koi ensure the descaling method you choose won't harm your fish.