First rule: keep trust in nature and wait! The green shimmer between the water lilies is completely harmless, but still does not correspond to the dreamy idyll that you as a proud garden pond owner have in the back of your mind. A particularly smart idea would be to buy water fleas that, after a few days in the pond, Blue or green algae keep busy at bay. The daphnia, as these completely harmless to humans are also called river flea shrimp, is available as live food in specialist shops.
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Phosphates in the water promote the formation of algae
Whether your pond water suffers from an excess of nutrients and is therefore too rich in phosphate can be determined very quickly with a test kit from the pharmacy. The ideal value is below 0.035 mg / l; if it rises, it massively favors the development of green algae and your commitment is required. Other negative factors are the high seasonal water temperatures in the pool and particularly intense solar radiation, which lead to an increased formation of green algae in the water pond. Other causes of rising phosphate and (thus also) nutrient values include:
- strong rainfalls (pH values change);
- Exposure to scattered plant and lawn manure;
- silted pond floor due to leftover food, fish droppings and dead plant parts, etc.
First aid for green algae in the garden pond
If the algae infestation does not subside on its own even after several weeks, a thorough renovation of the pond floor and the bank areas would have to be considered. This means that the so-called sludge layer in the water basin may be removed together with the pond soil. After the aquatic plants have been vigorously cut back or have been divided, it is better not to put them in soil, but on substrate and with the help of plant baskets in the individual ones Pond zones.
Use natural algae fighters
Frog bites, crab claws, duckweed and other floating plants also help natural ways to deprive the algae of nutrients. Therefore, at least a third of the pond area should be overgrown. In practice, even small ones have become fountain and cascades that ensure constant movement of the water and significantly reduce the formation of green algae in the garden pond.
Tips
A positive effect for regulating the pH value is achieved if a thick oak branch is placed in the pond water. Due to the released tannic acid, the survival conditions for green algae deteriorate considerably. However, before decomposition occurs, the wood has to get out of the pond again.