How long is the standpipe for the return in a Nexus+ that is pump-fed?

The return pipe is 40.5cm long in the 220 and 46cm long in the 320. This is a length of 4" pressure pipe which is factory fitted during production to the return chamber of the Nexus and sets the level of the water in the Nexus. It is removed when using the Nexus in a gravity fed pond. This can be quite difficult to retro fit as the hole is quite tight, you may find it easier using 110mm soil pipe as this has a slightly smaller outer diameter.