Try out this link
http://www.skippysstuff.com/biofiltr.htm
"matrix j" wrote in message
...
I am wanting to make a biological prefilter out of a large flat
rubbermade container using some coarse and medium density pads and
springflo for the bio medium.
The pre-filter will be placed at the bottom of my pond.
Pondmaster and little giant sell theirs for around $60 for a SMALL 12 x
12 or 12 x 24 size...but they look very easy to make.
Anyone have any links?
TIA