The filter I seen looks alot like these except the guy
didn't have holes in it to drain.

John Rutz has/had a veggie filter designed this way. I believe there
are pics of it on his site.

John's page link: http://www.fuerjefe.com

Jim
Zone 8a - Dallas, Texas
Pond, Veggie Filter, Pond Maintenance & Pond Tour Pics:
http://community.webshots.com/user/dallas75248