do i need a filter?

[cheeseburger]

ok so im going to build a 20'x7'x4' about 4200 gallons and im wondering if i need a filter for it or can i just use plants?
it will have koi

ok if i do need a filter would the third choice on this link be good enough
http://www.pondmarket.com/catalog/i...-and-pond-waterfall-filter-kits.cfm?aff=39378

with this pump
http://cgi.ebay.com.au/Water-Pump-1...ryZ20754QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

[frasertheking]

depends how heavy you want to stock ?koi are big messy fish so you will need a lot of plants to keep the pond healthy and the water would always be messy as they like to dig along the bottom looking for food.as for the filter it is a hell of a lot cheaper to build a filter,those filters are just fancy boxes.

 

[cheeseburger]

okay so can you tell me how to build a filter for a 4200 gallon pond
im 12 just to let you know but ill manage
how many koi could i have or be ideal?

 

[cheeseburger]

damn pond liner is expensive
i mean its gonna cost me like $200
OR MORE!!!

 

[frasertheking]

yeah ponds are not cheap, plus once you get the liner you need the filter, pump, fish,food and the running cost of it adds up.

for filter http://leisure.prior-it.co.uk/jims-pond-blog/2005/09/improvements-on-skippy-fish-pond-bio.html
tonnes of plans and info
http://www.mikebentley.com/ponds/homemadefilters.htm.
just aim to build as large a filter as possible.

 

[Muske]

The size of pump used will determine the number of Koi. Even though you don't want a filter, you need a pump for aeration. And since you have a pump you might as well use it to filter the water too boot. Try a bog filter w/ a lot of plants to filter the water.