"George" wrote in message
news:R6J4e.5965$g65.2835@attbi_s52...

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.

It's a nice looking filter. As for my filter, it seems to work for my pond
size and fish load, so I'm happy with the results. I clean the filters once
or twice a season depending on my mood. The pond ran on autopilot prior to
buying the house for atleast 2 years if not more. I used a shovel to empty
scoup out the much build up from the bottom of the pond, so anything less
then that is fine with me. As long as the water is clear enough to see the
fish near the bottom I'm happy.

-S