Green Water in Your Fish Pond; Solutions

Apart from the plants and fish, clear, sparkling water in your pond brings the most enjoyment and satisfaction. Many water gardening enthusiasts mark their success by the level of pond clarity.

Brown or blackish water is usually experienced in the spring, but also can occur during the regular season. This condition is caused primarily by decaying organics and blown in soils. Ponds without filtration systems can count on this each spring. A good spring cleanout will remove the offending colour and odours. Pump out the water, cleanout the sludge, leaves and other decaying matter from the rocks and pond bottom. An adequate filtration system will help keep this issue a minor concern.

Probably the most bothersome problem with water gardening is the control of algae growth.
There are many different kinds of algae in the world, but pond and water feature owners deal mainly with 1) Suspended Algae and 2) Filamentous Algae, or String Algae.

Suspended Algae consist of millions of microscopic plants that are suspended in the water, giving the ‘green look’ not unlike the appearance of pea soup.

Filamentous Algae, or String Algae, form tangled strands of hair-like growth. It attaches to plants, rocks and other surfaces, and during a heavy infestation can completely choke the pond.

We need to recognize that algae is not a bad plant, or pond weed. It is a part of nature, and is actually beneficial to the water feature eco-system. These single cell plants help remove waste and toxins from the pond water.
Only when algae over run a pond does it become a problem. A well-maintained and balanced pond will keep algae growth at an acceptable level.

CONTROLLING THE GREEN 1-CELLED MACHINE…

Algae, like all living plants require nutrients and sunlight to live and grow.
Therefore it stands to reason that by reducing one or both of these life-sustaining items,
Algae growth will be diminished.

REDUCING NUTRIENT LEVELS and AVAILABLE SUNLIGHT

If you raise fish in your water feature, know that your ‘pets’ contribute directly to algae growth. Fish food that is uneaten sinks to the bottom and decomposes, increasing nutrient levels. This in turn encourages algae bloom. Never over feed your fish! Follow the advise of the Japanese Sage;
“ A hungry Koi is a healthy Koi “ to which I might add, “ A hungry Koi sees clearly! “
Your fish can comfortably survive off aquatic plants, algae and insects.
Fish should be feed no more then twice a day, and only in amounts that can be eaten in several minutes. Anything beyond this is waste.

Overstocking your pond with fish will add significantly to algae bloom. Too many fish can lead to high ammonia levels, due to fish waste. This ammonia is broken down in the nitrogen cycle to nitrates, which algae feed on. Excessive levels of algae in the pond not only clouds the water, but during the night in algae’s growth phase, large amounts of oxygen are absorbed, robbing your fish of their needed supply of oxygen.
A general rule of thumb for stocking your pond with fish is one inch of fish length for every square foot of pond surface area.

An additional means of reducing nutrient levels is equipping your water feature with an adequate filtration system. This could be a simple, home made design using items found at the hardware store, to specifically designed systems supplied by your local garden centre. Filtration removes suspended organic particles that otherwise would settle to the bottom of the pond. These items decompose over time, adding to excessive nutrients.

Another way of reducing available nutrients is adding aquatic plants to your water garden. Not only will these plants compete directly with the algae for food, but these above surface plants form the ‘ roof top’ of the pond ‘forest’, capturing sunlight that would normally be used by suspended and string algae!
An added bonus is the floral and foliar beauty added to the water gardening experience.
Floating plants include the most common, both the Water Hyacinth and Water Lettuce.
These plants grow and reproduce quickly, absorbing huge amounts of nutrients.
Marginal aquatic plants will do the same, while at the same time visually softening the water feature’s edge.
Oxygenators soak up both sunlight and nutrients through their leaves, while providing good protective cover for fish and their fry.

The last, but not least important way of algae control through nutrient reduction is through the introduction of beneficial bacteria to the eco-system.
These bacteria can be purchased at your local garden centre. Bacteria come in a freeze-dried or liquid form, and perform beautifully in turning green water to clear water.
Bacteria convert the toxic ammonia to nitrates that are then absorbed by plants. Bacteria feed on these nutrients, reducing the amounts available to algae. Note: for bacteria seeding to work properly, the pond must have an adequate filtration system.

Removing clumps of string algae by hand is also an effective way of algae control. Dig this into the surrounding gardens for it’s nutrient value.

Be sure to control water run off from the surrounding lawn and gardens. Fertilizers and pesticides will not only contribute to algae blooms, but can cause toxic shock to the ponds aquatic life.

Your water feature will develop it’s own cycles of algae growth and decline. Do not be shocked if in the spring there is heavy algae growth. During the spring algae is the first plant to take advantage of the over abundance of pond nutrients. Levels will drop as the fish begin feeding, and bacteria and plant life re-establish themselves.

In conclusion, be assured that a well-maintained pond in short order will return to a balanced eco-system, providing all residents with a healthy and nurturing home.
And you will be able to SEE the fruits of your labour!

Till later, C Storm