Algae are simple, plant-like organisms that can grow in both freshwater and saltwater environments. They thrive in warm, sunny conditions and can rapidly multiply when excess nutrients like nitrogen and phosphorus (from fish waste and uneaten foods) are available in the water. While some algae are beneficial and serve as food for aquatic organisms, excessive algae growth, or algae blooms, can be problematic and unsightly!
Types of algae:
-
Green Algae: The most common type in ponds, which can turn the water green and make it cloudy.
-
Pro-tip: the best way to combat green algae is by using Ultraviolet Light
-
Blue-Green Algae (Cyanobacteria): Not technically algae but bacteria that can form slimy mats and produce toxins harmful to aquatic life along with dangerously low oxygen levels.
-
You might need to use liquid additives to fight this
-
String/Hair Algae: Forms long strands that can clog filters, cover surfaces, and reduce the aesthetic appeal of ponds.
-
Large clumps of algae should be manually removed and then beneficial bacteria and plants can be added
Impact of Algae:
-
Poor water quality: In contrast to the daytime, algae use oxygen during the night, and they can deplete oxygen levels in the water, stressing fish and other aquatic life.
-
Reduced light penetration: Dense algae growth can block sunlight from reaching submerged plants, disrupting their growth and affecting the overall pond ecosystem.
-
Floating plants are a great way to add shade - keep reading for more information!
-
Aesthetic and health issues: Excess algae can make the pond look unappealing and may lead to unpleasant odors or declined water quality.
Is there such a thing as "good" algae?
Glad you asked! Not all algae are bad for your pond - and trust us, you’ll never get rid of ALL of it. In fact, some types of algae, like diatoms, play an important role in maintaining a healthy aquatic ecosystem!
Good algae can be beneficial in several ways:
-
Food source for aquatic life: Many fish, like koi, eat algae!
-
Oxygen production: Algae, like plants, undergo photosynthesis and release oxygen into the water during the day which helps improve water quality.
-
Natural water filter: In small amounts, algae help absorb excess nutrients from the water, much like aquatic plants.
-
Support for the ecosystem: Algae can be a key component of the overall pond ecosystem, providing a stable environment for microorganisms that contribute to the nitrification process and other biological cycles in the pond.
How adding plants can reduce algae growth:
One natural and effective way to control algae growth in ponds is by introducing aquatic plants. Plants help balance the ecosystem by competing with algae for nutrients and reducing sunlight exposure, not to mention they can greatly enhance the aesthetics of your pond. Here’s how they work:
-
Nutrient competition: Aquatic plants absorb excess nutrients from the water, including nitrates and phosphates, which are the primary food sources for algae. By taking up these nutrients, plants starve algae and prevent them from proliferating.
-
Shade and light reduction: Floating plants like water lilies or water hyacinths, as well as tall submerged plants like cattails or hornwort, provide shade by covering the surface of the pond. This reduces the amount of sunlight that penetrates deeper into the water, depriving algae of the light they need to grow.
-
Oxygenation: Plants also contribute to oxygenating the water, especially submerged plants, which release oxygen during the day. This helps improve the overall health of the pond and supports the nitrification process.
-
Stabilizing pond conditions: Aquatic plants help stabilize water conditions by providing natural filtration, which helps reduce nutrient load and improves the overall water quality of the pond.
Which plants are most effective against algae?
Learn what zone you live in to make sure you are selecting appropriate plants for your climate!
-
Submerged and Shallow Water Plants (e.g., Hornwort, Hippuris Species, and Vallisneria): These plants grow beneath the surface, absorb nutrients directly from the water, and provide oxygen. They are excellent at competing with algae for nutrients.
-
Floating Plants (e.g., Water Hyacinth, Duckweed, and Water Lettuce): These plants float on the surface and create shade, reducing sunlight penetration to algae below.
-
Marginal Plants (e.g., Cattails, Iris, and Pickerel Rush): These plants grow along the edges of the pond and help with water filtration by absorbing excess nutrients.
Play It Koi allows you to search for plants by zone - making it easy for you to choose your favorites! By maintaining a balance of plants in your pond, you not only improve the aesthetic appeal and health of the pond, but you also naturally keep algae under control.