Is a settlement chamber needed contained by a koi pond? If so what is is used for? ...

When and how do I prune my nandina...
Answers:    No but it's nice. It's a filtration system that allows gravity to drag the solid waste out of the pond.
As you can see they are fairly expensive even though they save YOU seriously of time and energy.
http://www.azponds.com/vortex_filters.ht...
My solution install a big/oversize skimmer for the pond size and run two bio filter off the outlet. Then purchase a $300 Pond Vac II. Doing adjectives of the work myself to keep it cleaned out.
You can bid on them here and shipping is free
http://www.azponds.com/pondovac.html
Or Email this man for information he is usually speedy to respond.
He helped me abundantly when I was only just learning.
markmoser@azponds.com