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newsreader · 24-06-2007, 12:03 PM posted to rec.gardens

wrote:
My backyard pond is failry new (this spring) and the water is always
green. I've tried the chemicals, cleaned the filter and added lillies
and other vegetation to block out the sun. Nothing works! The water is
green as ever, any suggestions?

I'm in agreement with all the others suggesting more plants. A couple
other suggestions:
Minimize feeding of your fish. The most common cause of pea soup water
is excess nutrients, caused by either / or too many fish, or overfeeding
of fish. Most fish food is quite high in phosphates. Excess phosphates,
along with nitrogen, and algae flourishes.
If you already have a good number of plants, and still have lots of
algae, another good thing to try is adding Potash to the pond. Buy a
small bag of Muriate of Potash from you local garden center. It's very
cheap. I add a small handfull to my roughly 1500 gallon pond every
couple of weeks during the summer months. Very unscientific dosing
method I use is, when the Red Stem Parrots Feather & Water Celery, or
Hyacinths & Water Lettuce seem to be slowing in growth, or are not that
nice deep dark green, time to add more potash.
Higher plants typically need all 3 of the major nutrients to thrive.
N,P,& K on a fertilizer bag. Algae, however, will thrive on only one or
two macro-nutrients. A shortage of K, which is seldom high in a pond,
will allow algae to take over. With a more balanced nutrient mix, the
higher plants can out-compete with the algae for available N & P, and
the result is clear water.
I also periodically add a bit of Liquid Iron/Trace Element to the pond.
You can buy high priced (& very diluted) trace mix from a pond or fish
store, which comes with specific dosage instruction. I'd prefer my money
to be in my own pocket, so I buy the quarts of Iron/trace concentrate
from the garden center, and add a teaspoon or so at the same time I add
potash.
HTH