Here are my 2 cents only because I think I went through the same thing.
I could see 3 inches into the water and the plants were feeble at best.

first of all, no matter what, the fish like the algae, they're happy, so
be happy.

By washing your filter out every week you're washing off the bacteria
that will help kill the algae. You're also washing off the other
bacteria that remove the ammonia, but since you have such a small number
of fish that probably doesn't matter. If you want to know what I'm
talking about with regard to bacteria killing algae take a look at
http://www.koiclubsandiego.org/GRENH2O.html. This seems to explain what
is going on with my pond, even though nobody else seems to talk about this.

I have a prefilter to catch the gunk. I have a contraption with a 4' x
4' piece of nylon batting that I run the water through before it get's
to my filter. I rinse the batting out once a week and it has a ton of
green gunk in it. I have it set up so I can tell when it's getting full.

What kind of filter media do you have? I used to have something like
pea gravel (only much smaller) and it plugged up with the green crud. I
replaced it with media that has more open space in it. I use straws.
Strapping tape and stuff like that would work well.

It took a month for the filter to mature and help clean the algae out.
My pond is oscillating now. Some days I can see 2 feet down, some days
clear to the bottom (3 ft). I figure anything beyond 1.5 feet is gravy
because I can see the fish fine. My plants are doing much better. I'm
hoping some day I'll have enough plants that are healthy enough that the
green gunk in the prefilter won't be a problem anymore.

Good luck.

Matt


Szpond wrote:
I've written for suggestions before, and have tried them all...but, I STILL
have a nasty, green pond. I had clear water for 1 week since spring. I'm
really discouraged and do not know what to do. I had that "floating" algae for
over a month, that has stopped, but I still can't see my fish. Plenty of
plants, although they are not doing half as well as they did last year.
Bio-filter (85 gallon) which is just full of green, gummy, slimy crap
constantly. I think I might be defeating my own purpose - have been rinsing
out filter and media weekly - it gets that gummed up. Last year we only
cleaned once.

History: 2nd summer for pond.
SIze 14'x12'
Gallons: appx. 4200
Depth: 2 1/2 - 4' deep
Fish 3 koi 6-7"
2 koi 3"
Baby comets (maybe 40) from last year - (their mommies eaten by
the heron)
Waterfall and spitter
Full sun
Thanks for any ideas, suggestions. I didn't want to add chemicals to the pond,
but I'm ready too now. What works? I have been using BZT, no help, no change.
Thanks, Cathy