The small algae are difficult or impossible to fish out of the water. This can only be remedied with an appropriate filter system.
Causes of cloudy, green water
The green color of the pond water comes from an explosion of the existing algae. One speaks of an "algal bloom". In extreme cases you can only look a few centimeters deep into the water, then everything is cloudy.
A healthy pond helps itself. If he doesn't, the ecological balance is disturbed, something is wrong. Usually there are too many nutrients in the water. There are various reasons for this:
- Lots of mud on the bottom - from dead plant parts, leaves
- Dead plants in and around the water
- Fish droppings and leftover fish food - the more fish in the pond, the more nutrients
- Lots of rain that washes soil and fertilizer from the garden into the pond
- Well water - often contains a lot of phosphorus
- Too few plants that are responsible for breaking down the nutrients
- Lots of sunlight
- Few floating plants
- No pond filter
Immediate action
Immediate measures can help you quickly, but they do not help much in the long term. It is important to find out the cause of the algal bloom. That must be turned off. It usually takes longer. Therefore, something must first be done quickly to prevent the pond from tipping over completely.
UVC clarifier
If the water in the pond is filtered, i.e. a filter is installed that clarifies it, a UVC clarifier can do a lot. This must be installed in front of the actual filter. The decisive factor here is the size, i.e. the wattage of the UVC lamp. 1 to 2 watts are required for every thousand liters of water. If there are fish in the pond, it is 2 to 3 watts per thousand liters, in koi ponds even 4 to 5 watts.
In the UVC clarifier, the floating algae are "clumped" by UV light. These bundles can be filtered out by the pond filter. With the larger particles, the filter does not have the problem that there is with microscopic algae. They just slide through.
Tip:
Algae control agents
There are different algae control agents. For all of them, you should absolutely follow the operating instructions. Overdosing must be avoided. Chemical flocculants with the active ingredients ferric chloride or Aluminum salts work quite well. They ensure that the floating algae clump together to form large flakes and so they can be disposed of through the pond filter.
If the flakes sink to the bottom of the pond, they serve other algae again as nutrients. Flocculants work quickly and are harmless to other pond inhabitants.
Water change
This is where the scholars argue. Some recommend changing the water regularly, others say "just don't". New water should bring new nutrients into the pond. It certainly depends on the water itself. Rainwater is often quite acidic. Tap water can be very hard. It always depends on where the water comes from. Well water can be very good, but it can also contain a lot of phosphorus. Only a water test can help here.
Eliminate causes
In the long term, the only thing that helps is to find out the cause of the green water and to turn it on. The water values provide information about what is wrong. A water sample does not necessarily have to be sent in for analysis, a water analysis set is sufficient. This is available in stores with good instructions. Good water quality is characterized by the following values:
- pH - 7 to 8
- Nitrite (NO2) <0.15 mg / l
- Nitrate (NO3) <0.50 mg / l
- KH value - 5 to 12
- GH value - 8 to 12
Once the values have been determined and compared, countermeasures can be initiated. Water conditioners can be used to compensate for the values. It is important to break down the excess nutrients, especially the phosphates, which are a staple food for algae.
There are different methods for this:
Too little vegetation around the pond and in the pond
- Use fast-growing aquatic plants, both floating and underwater plants. They are food competitors. Nutrients that the plants consume are no longer available to the algae. Also plant the edge of the pond. Plants are absolutely necessary if the water is to stay clean.
Too much sunlight, especially in fairly shallow ponds
- Shade water surface, e.g. B. through floating plants or sun sails
Too much mud on the pond floor
- usually has different causes
- Leaves that fell into the water in autumn and sank. Rotting leaves produce loads of nutrients
- Soil from the garden washed into the pond by rain
- Dust that settles, especially pollen. This is very nutritious.
- Pond soil - for planting
Remove sludge, by hand or with a sludge vacuum, preferably in early spring. Do not use soil or pond soil in the pond, they contain too many nutrients. Fish the leaves daily before they can sink. A leaf protection net is even better stretched across the pond.
Too many fish - check the stock and fish out the fish that are too many. There should be no more than 3 kg of fish per 1,000 liters of water. Fish droppings contain a lot of nutrients, the more fish, the more droppings. In terms of water quality, a pond without fish is much better and easier to keep stable. In addition, many other creatures settle there that would not have a chance if fish were to be found in the water.
Unused fish feed. What the fish do not eat in the first few minutes sinks to the bottom and remains there. Another source of nutrients. Use low-phosphate fish food and feed only a little. The fish should catch their own food, so they stay sporty.
Dead fish or animals in or near the water - the decomposition creates masses of nutrients. The animals have to get out of the water.
Dead plants - decomposing releases a lot of nutrients, so remove plants
Dead algae, e.g. B. Thread algae, when they break down, also release loads of nutrients. The algae must be fished, otherwise they form the basis for a renewed algae plague.
Bad water clarification due to missing filter. A filter must ensure good water quality, especially in fish ponds. When choosing, you should seek advice from a specialist.
Too much acid rainwater in the pond. Change water, replace about 30 percent. Use nutrient-poor water or, if you don't have it, use a stabilizing agent.
Prevent
Prevention is always better than cure. It is therefore important to prevent or reduce too many nutrients in the pond. to avoid. It starts with the planning of the pond. B. or whether you design the pond a little higher so that no soil can be washed into the water.
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Plan the pond so that parts of it are shaded. Deciduous trees in the vicinity cause problems (falling leaves in autumn,
Pollen in spring). Evergreen trees are better.
Ponds are often embedded in a depression. That looks good, but it has the disadvantage that when it rains heavily, soil is often washed from the beds all around into the water. So it is better to make the pond a little higher.
It is essential to set up a capillary barrier so that the water is separated from the earth all around. Water and earth must not have any contact. The lock must also be functional, so always check it!
Many plants by and in the pond extract nutrients from the water that they need for their growth. These are then no longer available to the algae. The plants act as a biological filter. Fast-growing plants are cheap, but they shouldn't overgrow either. This creates problems again, albeit of a different kind. Floating plants are also ideal for shading the water surface.
Pond maintenance - regular pond maintenance can prevent nutrients from entering the pond. The plants must be checked regularly for dead parts. These must be removed because when they decompose they form new nutrients. Remove leaves before they can sink to the ground. It is best to fish out daily in autumn. Once the leaves have soaked themselves with water, they will sink. Then it is very difficult to get them out.
Install an appropriate filter, especially if there are fish in the pond.
Tip:A UVC clarifier is often recommended or simply lamps that emit UV-C light. The pump directs the water into a special container, where it is massively irradiated. The light kills algae, germs and spores, but unfortunately also bacteria. Their job is to decompose the algae and convert toxic nitrite into harmless nitrate. So every thing has two sides, but that is a well-known fact. Perhaps more harmless methods should be tried first before resorting to such intervening measures! A filter system with a circulation pump is usually sufficient to prevent the pond from turning green.
Conclusion
Pond water is never absolutely clear, at least not healthy. That is also not necessary at all. A viewing depth of 1 meter is usually sufficient. If the pond water turns green, this indicates floating algae. Under good conditions these multiply quickly and the water becomes greener and greener. It is important to find out the cause. Usually there are simply too many nutrients in the water that the algae need to develop. If you lower the nutrients, the algae are starved. They die off, but should be removed from the water because decomposing algae provide lots of new nutrients. Often it is fish that provide the nutrient input through excrement, leftover food and dead specimens. But soil, rainwater, leaves, pollen, sun, and missing plants can also be the cause. A pond is work, you have to be clear about that from the start. If you don't take care of yourself regularly, you shouldn't be surprised. Chemistry usually brings quick help, but it is not permanent. On the contrary, after an initial improvement, the situation usually worsens. Beware of these quick fixes. Better to think long term!