Understanding Algae

Rocky Mountain WaterScape
by Rocky Mountain WaterScape
Algae! That dreaded word! For most pond owners, algae becomes a problem every summer. Algae blooms are not uncommon even with a mature pond and often frequent with an immature pond. Although you will never get rid of all algae in a water feature, some is actually beneficial if you have fish or turtles, it can be controlled. The short, velvet type that clings to the pocks in the pond is beneficial, providing oxygen during the day and food for your fish. A little algae makes the pond look natural, but when the algae takes over it is time to conquer it!
There are actually many varieties of algae that can form in a pond. Some of the more common types are:
■ The filamentous algae is also referred to as pond scum and gives the appearance of a slimy, lime-green mat floating on the surface of the water.
■ String algae, also considered filamentous algae, grow in shallow water and attaches to rocks and plants. They spread and reproduce quickly and can “take over” a pond. They look like long green hair.
■ Free floating algae or plankton algae are often referred to as pea soup or just green water.
There are several causes of algae:
■ Algae needs food (sunlight, nitrogen and phosphorous) to survive. Food can come in the form of fish waste, fish food (from overfeeding fish), decaying organic matter (leaves that have fallen into the pond), grass clippings, pine needles, mulch, or lawn fertilizers seeping into the water.
■ Algae will often be found in new ponds while the water is becoming balanced. As soon as the pond is balanced and the algae is done consuming the excess nutrients in the water, it will die off.
■ In the spring, before the marginal and floating pond plants mature, the warmth and extra sunlight can spur an algae bloom. Plus leaves may have blown into the water over the winter and while they are rotting at the bottom of the pond, they become food for algae. A spring clean out will help to alleviate this.
■ Improper use of water treatments can promote algae.
■ Overcrowding of fish, too much fish food, and the quantity and quality of food given the fish can promote algae growth is not regulated properly.
Getting rid of unwanted algae:
■ Building a pond in a shady part of the yard, but not directly under trees that will drop leaves into the water will help with algae control.
■ Installing an aerator into the pond will add oxygen and create water movement.
■ Cover at least 1/3 to 2/3 of the ponds surface with floating plants, such as water lilies, lotus, floating hearts, water hyacinth or water lettuce. They compete with the algae for nutrients and sunlight; therefore, depriving the algae of nutrients.
■ Include submerged plants such as elodea or Anacharis, which also competes with algae for food.
■Turtles, snails and tadpoles will eat algae.
■Do not overfeed fish
■ Add beneficial bacteria on a regular basis which will compete for the algae’s nutrients.
■ Keep your filtration system clean.
■ Remove dead leaves and other organic materials frequently with a skimmer.
■ IonGens are another proven method of controlling algae.
Algae in a Pondless Waterfall
Free Floating Algae
Pond scum
Water lettuce competes with algae for food. It is a quick spreading annual plant in the Denver area! And beautiful!
Frequently asked questions
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