Thread algae control and prevention in the pond

What is filamentous algae?

Thread algae, also known as filamentous algae, is a type of algae found in ponds and other bodies of water. They are long, thin threads that stick together and form a dense layer. This can give an unsightly appearance to the pond and affect water quality. Excessive growth of filamentous and floating algae can reduce oxygen levels in the water, which can be dangerous to pond fish and other aquatic organisms in the pond. Fortunately, thread algae can be easily and quickly controlled and prevented by properly landscaping the pond.

What is the cause of filamentous algae?

Thread algae begin innocently as gossamer strands that attach to the pond edge, plants or rocks. Causes are:

1. Insufficient oxygen plants: Thread algae and oxygen plants are food competitors. If there are not enough oxygen plants to absorb nutrients from the water, filamentous algae have a growth advantage.
2. Low water hardness: Thread algae grow well in soft pond water, while oxygen plants do not.
3. Leaf fall: Falling leaves that decay on the pond floor release nutrients that promote filamentous algae growth.
4. Abundance of fish: Fish produce waste, which makes pond water more nutrient-rich and encourages the growth of filamentous algae.

Is filamentous algae good?

To a limited extent, filamentous algae can contribute to the pond ecosystem by consuming nutrients that might otherwise lead to an explosion of more harmful algae species. However, when they get the upper hand, they can interfere with other plants and disrupt the pond's biological balance.

How do you prevent filamentous algae?

1. Provide enough oxygen plants: Place enough oxygen plants in the pond so that they can absorb nutrients from the water.
2. Limit leaf fall: Span a net over the pond to prevent falling leaves.
3. Limit the number of fish: Too many fish make the pond water more nutrient-rich.
4. Remove filamentous algae by hand: This helps slow its growth.
5. The ultimate answer to thread algae is a properly designed pond: A properly designed pond promotes a natural balance, with each plant and organism playing its part in creating a healthy environment. This balance keeps the water clear and prevents excessive growth of algae such as string algae.

Control of filamentous algae

The best weapon against thread algae is not a temporary solution, but is to set up the pond correctly from the beginning, below are some essential points that a correctly set up pond should meet:

1. Pond substrate: A healthy pond bottom is crucial. A thick layer of pond substrate attracts beneficial bacteria that help purify the water and provides a stable base for plants.
2. Oxygen plants: They purify the water, provide hiding places for fish and marine life, and help regulate temperature and algae growth.
3. Water lilies: These beautiful plants provide shade, help regulate water temperature and provide hiding places for fish.
4. Marsh and aquatic plants: These plants play a crucial role in water purification and algae control.
5. Pond Bacteria: These microorganisms are your pond's unseen heroes, contributing to a clear and healthy ecosystem.

Tip: Freshwater mussels are also a great addition to a correctly designed pond, as they naturally purify pond water. One mussel purifies an average of 10 liters of water per hour.

Our step-by-step plan for a correctly set-up pond shows you step-by-step how to set up your pond correctly to prevent problems such as algae: Read our step-by-step plan.