"Snooze" wrote in message
m...

"CanadianCowboy" wrote in message
.. .
Just wanted to share a very inexpensive Bio Filter with some mechanical
filtering that can easily be built at home.

http://www.mvwgs.org/filter.htm

Good filter design, I made mine out of 2 milk crates, two costco bulk packs of
green scotch pads, and a few yards of gazebo screening fabric. I and a fairly
significant portion of this newsgroup do not recommend using lava rocks as
filter material. The pores clog up quickly and are difficult to clean, they
are heavy, and do not have a good volume to surface area ratio.

Consider removing the rocks, and using sun screen fabric, which you can get
from any hardware store. When it's time to clean the fabric, just spread it
out on the lawn, and hose it off. Light, easy to clean, cheap.

-S


Hmmm. If your lava rock is clogging up, then you are not pre-filtering (or
properly pre-filtering) the water first. Mechanical pre-filtering removes most
of the detritus from the water, which then flows through the scoria (which
should be colonized with beneficial bacteria) and comes out clean as a whistle.
I've been using scoria for three years, and have never had to worry about
cleaning it since the water is pre-filtered. The only thing I have to clean is
the pre-filter itself, which is very easy to do, takes about 5 minutes about
twice/month in the spring and once/month in the summer/fall, and rarely in the
winter. Sunscreen fabric acts as an efficient mechanical filter, but has
negligible biofilter properties, since by the time you get any benefit from it,
it becomes clogged and you have to clean it. Hosing it down to clean it will
not only get rid of the detritus that has built up, but will also get rid of
most beneficial bacteria that has colonized it. Adding Aquazyme or similar
product to the water is also beneficial to your pond. The bacteria not only
will colonize the filter, but will grow on any surface in the pond, and add to
the pond's natural filtering capabilities. Here is a link that shows the
specifics of my homemade design:

http://home.insightbb.com/~jryates/filter.htm

Of course, if can be adapted in many ways. This is just the way I use it, and
it seems to work very well.