Actually I pretty much stay confused on the subject of
filtration! I have a 10% - 15% of the surface area for a veggie
filter... then I've got a pressurized PF 3000 (supposed to filter
3,000 gallons of water .... HA!). Oh Yes, and thanks to Carolann
and John Rutz I'm
working on a TT. It will be built out of a milk crate. I use lots of BZT
and Koi /Clay and still worry about filtration. My 14 Koi seem fine ...
need to get rid of about a dozen goldfish, though.

You can see that the more filtration you have the more your going
to want... the neverending story of ponding.

Nedra
http://www.geocities.com/Heartland/Pines/4836
http://community.webshots.com/user/nedra118

"David Larson" wrote in message
...
David Larson wrote:

RichToyBox wrote:

David,

As for whether it is best for the water to run upflow or downflow, a
well
drained downflow, free to allow air into the media is probably the
best and
is known as a trickle tower. If the filter is full and used for
plants on
top, then upflow is easier to plumb and maintain a water level. The
bacterial surface area is the same, the difference with trickle tower
is the
additional aeration available.

Thanks for the reply! Your idea of the trickle tower makes sense,
seeing how this is the method
used in sewage treatment plants.

My next question is this -

Is there is a formula to figure out the cubic feet (or surface area) of
filter media one would need?
Let's say the pond will be 3,000 gallons.


OK, I just did a google search on this topic, and I am even more confused
now! Some people say the
media surface area should be 5% of pond surface, or 10%, or 1/3 or based
on weight of all your koi, or,
or, or ......... YIKES!!!

Isn't there a simple tried and true way to figure this out?

- David