My pond is a pre-formed liner. I made the bio-filter based loosely on the Skippy filter...
http://www.skippysstuff.com/biofiltr.htm
http://www.skippysstuff.com/minime.htm
I took a large plastic decorative pot, ran the 1/2 tubing from the pump in to the bottom, filled it with bio-degradable...
I was going to try the wet/dry shopvac. Not sure if it will work, but I am going to give it a go. I will let you know how much of a disaster that turns out to be
I have a 500 gallon pond. I have a large bio filter so I don't clean it. It has been a couple of months and I DO need to suck the sediment out of the bottom. I will put that muck in the garden somewhere