My pond looks like green pea soup.
What can I do?

Green water is caused from microscopic, single celled algae that grows
suspended in the water. It comes from out of the environment. Heat, light,
and nutrients are three things that cause it to grow rapidly in your pond.
The heat and light come from the sun and short of installing a shade over
the pond, it is very difficult to control these two. Also, installing a
shade over your pond will limit greatly the types of plants you can grow in
it. The best way to shade and cool your pond is with aquatic plants.
Besides being very attractive, a plant cover on your pond of at least 50%
will give you all the shade that your pond needs. Plants also remove the
nutrients, the third requirement for controlling green water algae. The
more plants you have, the faster the nutrients are removed. Without the
nutrients, the algae dies and the water clears.

How it all works:

There are two types of bacteria that convert ammonia wastes from the fish
and decomposing organic matter. One type converts the ammonia to nitrates.

The other converts the nitrates to nitrates. The plants can then absorb
these nitrates and remove them from the water. These bacteria occur
naturally and live in the pond, a few on the liner, but mostly on the rocks
& gravel.

How can I help speed up the clearing process?

Stop feeding the fish. The algae and the plants provide enough for them to
survive. Feeding the fish just adds more ammonia to the pond and overloads
an already bad situation. Add rocks & gravel to give more surface area for
more of the beneficial bacteria to live. Add bacteria concentrate. This
will give your bacteria a jump start to get it growing. Add lots of plants.
Especially water hyacinth and water lettuce. Any plant that floats in the
water uses a lot of nutrients to grow. The nutrients are removed directly
from the water. Plants like waterlilies also shade and cool the pond.
Increase circulation. Anything you can do to move more water will help the
bacteria and plants do their work. Add a Biofalls. These units have filter
mats and rock that provide a large area for the beneficial bacteria to live.
Be patient. It takes time for all these things to become established and
begin working. But once the pond balances it will stay clear with very
little maintenance.

But I'm not patient. I want it now!!

Ok, add a UV filter unit. These units with the correct pump will clear your
pond in a matter of days (sometimes a few hours). They do have a few
drawbacks. They are expensive, especially if you have a big pond. They
correct the symptoms, not the problems. They are great for clearing a pond
until the bacteria and plants are established. If you use them for extended
periods of time, make sure you keep a watch on the ammonia levels in the
pond. If the bacteria and plants aren't taking care of the ammonia it can
build up and kill your fish.

by John Cash
of Ark-La-Tex Water Gardens