Closed-off surface waters are subject to natural fluctuations caused by the input of plant matter. If there is an explosive proliferation of algae, the parameters in the body of water are no longer in balance. But home remedies usually make the situation worse.

Algae often grow particularly well when it is warm

Table of Contents

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  1. the essentials in brief
  2. emergence
  3. Fight
  4. Permanently improve water quality
  5. Inappropriate means
  6. species of algae
  7. frequently asked Questions

    8. the essentials in brief

    • Algae develop primarily when there is an excess of nutrients and when there is a lot of heat
    • Algae can be effectively combated by vaccination, water exchange or snails
    • It is essential to refrain from treating the fish pond with household remedies such as milk or vinegar

    Why are there algae in the pond?

    Algae, like any plant, need nutrients and sunlight. In a pond with a balanced concentration of nutrients, the different species live in coexistence. If the phosphate content increases to more than 0.035 milligrams per liter, the living conditions for algae improve. In the summer months, the water warms up considerably and the incidence of light increases in the lower layers. When all conditions are in favor of algae growth, there is often an explosive proliferation.

    Bodies of water are constantly changing. Under natural conditions, an equilibrium is established automatically.

    Possible nutrient sources:

    • Fish droppings or excess feed
    • Flushing of nutrients from fertilized lawns and beds
    • Autumn leaves and pollen sinking to the bottom of the water

    Do algae in the pond produce too much oxygen?

    The plants release oxygen through the smallest pores. This rises to the surface of the water in the form of small bubbles. The more algae grow in the water, the higher the oxygen production. This is cyclical because the plants consume large amounts of oxygen at night. Dead thread algae sink to the bottom and are decomposed by microorganisms. Oxygen is also required for this. In an unbalanced ecosystem, this can be fatal for the fish.

    Algae consume and produce oxygen

    digression

    pH and KH value

    A stable pH value is important for a pond because it also influences other parameters in the water. The value depends on the water or carbonate hardness, which is referred to as the KH value. If this is too low, the pH will fluctuate. However, this value is also subject to natural fluctuations over the course of the day. The optimum pH value for a pond ranges between 7.5 and 8.5. The more turbidity and nutrients are present in the water, the higher the value increases. If this is more than 8.5, an algal bloom is not far away.

    What helps against algae?

    Bodies of water are sensitive ecosystems that react strongly to changes. Flora and fauna can develop in different directions within a short period of time. These processes largely depend on the means you use. In principle, you should not pour chemical products or home remedies into the pond. They do not correspond to the natural state and can do more harm than good to the water body. Excessive amounts of algae should be fished with a net. You can easily dispose of them in the compost.

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    Vaccinate

    Draw about ten to 20 liters of water from an intact pond and pour this into the eutrophic pond. In this way you bring numerous microorganisms into the water, which naturally curb the growth of algae. Alternatively, you can also use starter bacteria. These highly active microorganisms are added directly to the filter or simply to the water.

    nitrogen deprivation

    Store a jute sack (€10.99) filled with straw directly in the pond. Within four to five weeks, microorganisms ensure that the straw is decomposed. Large amounts of nitrogen are used in the process and the decomposed material can then be composted or used as mulch (€239.00). You can do a similar thing with peat, oak wood or barley straw pellets. These ensure that the pH value of the water is lowered and algae growth is restricted.

    renovation

    If new algae keep developing, you should think about renovating the water body. The entire substrate is removed from the bottom so that the pond is no longer polluted by fish droppings, uneaten food and rotted plant material. Replace the old pond soil with a nutrient-poor substrate. Prune or divide any plants vigorously before returning them to the pond.

    Permanently improve water quality

    A pump ensures that the water stays clean. Sometimes it happens that algae develop in the water despite the pump. Get to the bottom of the problem and instead ensure that the body of water is filtered naturally. A natural flora and fauna limits the growth of algae.

    Plants against algae in the pond

    The thousand leaf prevents an algae infestation

    Marsh and floating plants, or fully submerged plants, compete with algae because they also need nitrogen to grow.

    • thousand leaf: Myriophyllum spicatum or Myriophyllum verticillatum
    • buttercup: Ranunculus aquatilis or Ranunculus trichophyllus
    • waterweed: vigorous Elodea canadensis or Elodea densa
    • water hose: demanding Urticularia vulgaris or Urticularia minor

    Floating and marsh plants such as the aesthetically flowering water hyacinth, crab claw or water chestnut offer more variety for the eye. Plants from swampy locations in particular are strong consumers of nitrogen and are suitable for improving the pond quality in the long term.

    salad

    In theory, lettuce varieties can also be cultivated on the water surface. The weak consumers withdraw small amounts of nutrients from the water, which are no longer available to the algae. In addition, the floating islands provide shade and prevent heat build-up in the pond. In order to achieve success, however, many lettuce plants must be placed on the water.

    How to build a salad island:

    • Fill plastic pots with gravel
    • Insert lettuce plants
    • Put pots in a styrofoam ring

    This variation is a short-term way to lower the nutrient levels in the water. After a while, lettuce and the like stop growing. If the water is no longer sufficiently saturated with oxygen, the roots can no longer absorb nutrients. In addition, these begin to rot in the absence of air. In hydroponics, all parameters are therefore constantly measured so that they can be kept at a constant level.

    Which fish eat algae in the pond?

    Grass carp eat thread algae

    There are some species of fish that naturally clean the pond. However, they do not eat the filamentous algae but the free-swimming phytoplankton. An exception are grass carp, which like to eat plant food if not fed. The rudd remains relatively small at 20 to 30 centimeters and can also be found in the front garden pond. Like the silver carp, it belongs to the group of algae eaters. This species of fish feels at home in larger bodies of water. It grows up to 130 centimeters long.

    Snails against algae in the pond

    Aquatic snails are considered algae lawn mowers because they rasp the pond floor with their sharp mouthparts. Various species filter floating algae out of the water and eat the algae growth on rocks and the ground. However, gill breathers need enough oxygen in the water to survive. Lung-breathing snails come to the surface of the water to take in oxygen.

    • Gill Breather: Swamp Lid Snail
    • Lung breathers: pointed mud snail, ramshorn snail

    Inappropriate means

    Algae in the fish pond should not be combated with home remedies in order not to damage the fish

    The idea of fighting algae growth without chemicals is fundamentally positive. All home remedies aim to change a parameter in the body of water. Algae are combated in the short term, but these measures are not permanent. As long as the pond ecosystem is not in balance, no means will bring the desired success.

    Reasons against home remedies:

    • Aquatic plants and fish like stable conditions
    • short-term and strong changes in individual parameters weaken living beings
    • Algae recover faster from fluctuations than aquatic plants

    milk

    Milk contains lactic acid bacteria and large amounts of protein, fat and lactose. In the water, it not only causes turbidity, but also supplies additional nutrients. An even greater imbalance arises and the water quality suffers from the entry. It has not been proven that milk actually helps against algae. It is the same with bread drink.

    vinegar

    Vinegar is a natural remedy and is used to lower an acutely elevated pH value. The liquid affects the KH value, causing the pH to fluctuate. The acetic acid breaks down using oxygen, leaving salts behind. Fruit vinegars contain additional nutrients that can pollute the water.

    Unsuitable means with similar effects:

    • ascorbic acid or vitamin C
    • oxalic or oxalic acid
    • Citric Acid and Apple Cider Vinegar

    salt

    In colloquial usage, various substances are referred to as salt. Dissolved ions play an important role for a body of water. Pond plants and fish could not survive in an ion-free pond. Ions also ensure stable conductivity and influence the water hardness. The salt balance of a pond largely determines plant growth. Small doses of salt can have a positive effect on the water quality. However, other pond creatures that are adapted to freshwater often suffer.

    consists examples
    crystalline salts anions and cations Sodium Chloride, Calcium Chloride, Acetates
    salt sodium chloride Sea salt, table salt, black salt
    mineral salt inorganic nutrients iron, zinc, calcium

    zinc oxide

    Like copper, zinc is a vital substance that living things need in low concentrations. Zinc oxide is a white powder that is produced when zinc is burned in the presence of oxygen. It is largely insoluble in water and is considered hazardous to the environment. Because of its antibacterial effect, it should not be used in water. Although many field reports show positive successes in combating algae, the body of water is still thrown off balance. Important Microorganisms die, resulting in long-term damage.

    How Zinc Affects Algae:

    • Ions enter cells
    • oxidative stress occurs
    • decreased growth rate

    tips

    Refrain from adding baking soda to the water. It increases the KH value and can quickly affect plant growth.

    Types of algae in the pond

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    Some species overgrow surfaces, others swim freely in the water. There are also algae that develop conspicuous structures. Dead algae usually float on the water surface and form unsightly nests.

    floating algae

    These green algae are microscopic and swim freely in the water. Because they can multiply quickly, they ensure that the water is colored accordingly. When the algae bloom, the pond can be so cloudy that the depth of visibility is a few centimetres. This occurs in spring when temperatures rise, even before the pond plants begin to grow. Floating algae use the nutrients and grow until aquatic plants take the nutrients away from them.

    thread algae

    They can also grow in low water temperatures and in winter. Their striking growth habit makes them unmistakable. The algae develop long threads that root on stones, other plants or the bottom of the pond. Occasionally they form nests of algae floating freely on the water. Warm temperatures favor their growth, which is why they should be fished out of the water regularly.

    blue-green algae

    The slimy algae in the pond often hide blue-green algae, which are actually bacteria and not algae. These organisms float on the water surface and form a fur-like covering on the leaves and stems of aquatic plants. The unpleasant smell is typical.

    Why blue-green algae occur:

    • Filter system does not work optimally
    • too much ammonium in the water
    • excessive feeding of the fish
    • Fish ponds are heavily overstocked

    brown algae

    The brown algae are mainly found in deeper water zones. Their brownish to reddish coloring is typical. The algae grow on stones in the pond or colonize pond walls. These organisms also grow under a lack of light with low nutrient availability.

    tips

    Brown algae can simply be vacuumed off as they do not adhere particularly firmly to the substrate.

    beard algae

    Because of their structure, they are often confused with thread algae. Beard algae form long stolons and grow around plant stems. They often occur in ponds with a weak flow. They thrive in low levels of carbon dioxide and are favored by overfeeding. Beard algae are difficult to fish out of the pond.

    frequently asked Questions

    When does algae form in the pond?

    There are different types of algae that are adapted to different living conditions. The species occurring in garden ponds prefer spring and summer when there is a high availability of nutrients. They benefit from rising water temperatures and sunlight.

    What to do against algae in the pond?

    Fighting algae naturally is difficult. Bodies of water are sensitive ecosystems and should not be contaminated with home remedies. If there is heavy algae growth, fishing off the floating parts helps. Make sure there are enough plants growing in the pond. Water and marsh plants that sprout particularly early ensure that the algae do not have sufficient nutrients available.

    Are algae in the pond harmful?

    In principle, algae are not a problem for fish. They enrich the water with oxygen, which benefits aquatic life. If the ecosystem becomes imbalanced so that algae growth dominates, the fish can be adversely affected.

    Do aquatic plants help against algae in the pond?

    Aquatic and marsh plants are the best way to naturally limit algae growth. They extract nutrients from the water and provide shade so that the water does not heat up excessively. An intact pond contains various creatures that contribute their part to the functioning ecosystem.

    Why are there algae despite the UV lamp?

    The UV lamp destroys floating algae, but not filamentous algae. If the dead algae particles are not removed from the water immediately, they decompose and release nutrients again. Other algae that compete with the floating algae benefit from this.

Category:

Garden design