It is a modified bead filter. Great for swimming pools, not for fish ponds
or even ponds with fish. Of course the problem with bead filters always has
been they go anaerbic so I guess this is trying to add oxygen to overcome
that.

the easiest filter to make is a veggie filter. the added benefit is it LOOK
wonderful. Ingrid


"Hal" wrote in message
...
Some people think air in the bio filter is the greatest development in
fish keeping in a long time.
http://www.koivillage.com/filtration/nexus.html