"Paul" wrote in message
...
Thanks, but what do mean by add a "CELL". I have approx 20 goldfish in size
from 3" to 6" and three KOI sizes from 3" to 8".

Those goldfish will reproduce fairly rapidly and the koi will get very large in
a few years. In the next two years you will likely need a larger filter than
what you currently have made. What I mean by a cell is that you have a
rubbermaid box that you have converted to a biofilter. That is what I call a
cell. You can add another "cell" which will increase the capacity of the filter
by making another one and connecting it to the existing one or build a larger
one. But eventually, your load will become to high and you'll have to "cull the
herd".

"George" wrote in message
news:XrRje.25397$WG.8217@attbi_s22...

"Paul" wrote in message
...
Hi, was wondering if someone could tell me if I did the right thing here. I
built a Biofilter for my pond.It is 12X7X2. The one I built is 9gal.
basically a square Rubbermaid box. The pump (1200gph) pumps into the "top"
of box through an 18W UV light, then goes into filter through a 1 1/4" thick
Med. filter pad. It works its way down through the filter media. The media
is a combination of Bio Ceramic Barrels,Two bags of Lava Rocks crushed into
smaller sizes and regular Supra media, then finally exits out the bottom
into pond. Will this design keep water ok? Thanks..............

The efficiency of any biofilter depends mostly on the bioload in the pond. I
suspect that if your bioload is low to moderate, it should work well for you.
If it is high, you may want to attach an additional cell to the existing one.
Having said that, I wouldn't go through the trouble until you've let this one
run long enough to see if it is going to handle the load. If it does, then
you're done. If not, think about adding another cell. The wonderful thing
about biofilters if they are constructed properly is that you can always add
more cells to the flow (if you have the room).