[I did say, Cathy, that not everyone agrees with that web page, but
everything it said alligned with what I saw in my pond more than a lot
of other things I've read. I have 1300 gallons, not many fish, some
plants, and had lots of soup until I got my filter working.]


K30a wrote:
Nutrients for algae are sun, new water, fish waste, fertilized run off, rotting
plants, blown in dirt.
Dry to reduce or eliminate one or more of these.
I agree with Ingrid, try shading the pond.

Try reading that web page I referenced. He says shading the pond to
remove algae is a myth, as well as the idea that algae blooms are caused
by various nutrient concentrations. Based on his tests he said that
there's a byproduct from a type of bacteria that consume dead algae and
that is toxic to algae. So, Cathy's pond or filter needs a place for
some amount of rotting algae and it needs to sit there for a month.
This is why I said some sort of prefilter would enable Cathy to leave
her main filter alone long enough for this other type of bacteria to do
its thing. This is exactly what I did and now my pond is clear. This is
after 2 years of trying things I read on this newsgroup and getting
frustrated, as it sounds like Cathy is.

A uv filter would also kill the soup type algae and would do it sooner.
But eventually the filter will have to work correctly because the
fish load will increase to the point where ammonia is a problem. Of
course, with 4200 gallons and 2 small koi, 2 tiny koi, and 40 small
fish, this is going to be a few years. Anyway, as soon as the filter is
working the uv filter might not be needed anymore.

Since I just talked about Norm Meck's web page with "~jan JJsP" (see the
thread "pond filter") I'm signing off from this thread. Anyone can send
me email if they have questions.

Matt