Mucous and filamentous algae

Thread and slime algae have low temperature and water quality requirements. They can grow under conditions where micro life and aquatic plants cannot yet develop optimally. In addition, they absorb nutrients and trap sunlight so aquatic plants have less of a chance.

As their name implies, filamentous algae are thread-like. Long green threads that are first attached to walls and plants and resemble clouds. In the later stages of a growth, they often become detached and float. The color changes from green to yellow and brown and ends in a dirty mush.

In the presence of filamentous algae, the water is usually clear. The presence of filamentous algae indicates very low or absent phosphate levels and low nitrate levels. After winter, there are almost inevitably some residual nitrates in the pond water. The filamentous algae take advantage of this and grow until the nitrates are depleted. Then they stop growing, let go and appear as yellow-brownish-green slippery tangles floating on the water surface. Additional effects are low KH and high pH and almost always stagnation of oxygen plant growth.

Thread algae control

How can you fight thread algae? We have some tips for you:

• Place more pond plants in your pond that do not rely on water for their CO2 supply. Plants that do not live only under water such as floating plants, water lilies and marsh plants
• Cover 50% of the water surface with plants, so that they absorb the nutrients and algae have no chance to grow
• Check the pond water: an ideal GH value is between 8 and 12°DH. If necessary, bring the hardness level up
• Activate micro life with resources intended for this purpose
• Remove filamentous algae from the pond regularly and as much as possible. Removing this algae does remove an oxygen source, so the advice then is to aerate.

As the plant stock grows and increases in size, the growth of filamentous algae will decrease.

Thread algae removal

To remove thread algae, you can use an algaecide once or repeatedly. This works fine; the algae disappear quickly. But, it does not remove the cause of the blue-green algae. So, without the above measures, the growth of blue-green algae will start again.