How To Get Rid Of Algae In Fish Tank – Algae Types And Treatment

How To Get Rid Of Algae – Algae are lower aquatic plants that do not have roots, stems and leaves. Algae, depending on the species, can develop by attaching themselves to various underwater surfaces. It also lives freely in the water column. Algae have various colors including black, red, green, blue, purple. Some algal cells contain only chlorophyll, while others contain a certain amount of pigment, which in turn gives the algae a different hue.

They also differ in appearance – these are either fluffy bunches resembling moss, or long strands, or something resembling a slimy coating. Many people remember the mud in an ordinary pond – this is also algae. The presence of algae is inevitable where water, nutrients and light are simultaneously present.

One of the biggest problems of all aquarists, without exception, is the prevention of the appearance of algae in their aquarium. As well as the use of effective methods to combat them. In any aquarium, changes in water parameters and other components can occur, which in turn can have a beneficial effect on the rapid development of algae.

Sometimes it even happens so, the aquarists, faced with the problem of the appearance of algae in the aquarium, simply give up saying – “I can’t do anything”, “I’m tired”. But there is a famous English proverb – ” Nothing ventured, nothing gained “, the same is the case with an aquarium, you should not be afraid of imaginary difficulties.

In reality, algae in an aquarium is a problem that can go global and lead to a situation where, unfortunately, only a completely resetting aquarium can solve it. It is very important not to make your aquarium that way. Well, if you look at the reasons, things are not as difficult as it seems at first glance.

How To Get Rid Of Algae In A Fish Tank

The aquarist’s first rule for getting rid of algae is to have a basic knowledge of algae, know the reasons for its appearance, and take the necessary action in time to solve this problem. After some time and with some experience, it will not be difficult for an aquarist to tell which type of algae you have, and most importantly, he will know how to deal with it. we recommend not to bring these problems to rapid development, but “cut off their appearance as they say at the root.” The second rule is to prevent the appearance of algae in the aquarium.

“Once algae development starts to dominate plants, it will be very difficult for aquarists to control it.”

In this article, we will discuss the different types of algae that cause problems in freshwater aquariums. We will find out the reasons for their appearance, and also tell you about how to control their growth. First, let’s compare aquatic plants and algae to understand what are the similarities and differences between them.

Read Also: Aquarium Algae Eaters – The Most Popular Helpers

Aquarium Plants And Algae

It is important to understand that light, water and nutrients are essential for the normal development of both aquarium plants and algae. Algae also appears in herbal aquariums with clear water and beautiful aquatic plants. What is the secret of the fact that algae dominate some aquariums, and some of them are invisible.

Every surface, including plant leaves, contains a thin layer of algae, bacteria, worms and other microscopic organisms. If you look at a drop of aquarium water under a microscope, however clear it is, you will be sure to find life in it, including the large number of algal cells swarming within it. In beautiful plants with clear water, algae growth is in balance with plant growth. This is the most important secret to successfully maintaining live plants in aquarium.

Aquarium Plants And Algae

It is impossible to avoid the growth and development of all algae in an aquarium with live plants. Algae are an important part of the food chain. They also help maintain a healthy biological balance, which is ultimately the path to a beautiful aquarium with healthy and vibrant plants.

Interesting fact. Scientists have proven that actively growing aquatic plants release compounds that inhibit algae growth. This process is also called allelopathy *, and it’s the one that helps maintain the proper ecological balance of the aquarium. This may seem strange, but it is a fact. Plants need algae, and algae need plants. It is a symbiotic relationship of mutualism of existence with each other – this is how our nature took care

* Allelopathy – the property of some organisms produces one or more biochemicals that  inhibit or suppress the germination, growth, survival, and reproduction of other organisms.

Usually certain types of algae appear when a new aquarium matures. Under normal conditions, different types of algae will appear and disappear as the aquarium matures and a balance is established between the types of algae. The key to minimizing algae growth is to create an environment conducive to plant growth, which in turn inhibits algae growth. In general, this means maintaining stable carbon dioxide levels and tightly controlling nutrition so that plants can keep growing and the algae starve.

Well, it is time to talk about the most common algae in our aquarium, as well as learn the reasons for their appearance and, surely, about how to effectively get rid of this unpleasant algae.

Blue-Green Algae

There are many types of blue-green algae that can appear in your tank. The most common species are Anabaena, Microcystis and Aphanizomenon.

Under pleasant habitat, blue-green algae can grow very quickly, covering soil and plants with slimy blue, green, purple, red or brown blooms. It has a characteristic earthy odor. In fact, blue-green algae are not real algae, physically they are photosynthetic cyanobacteria that grow in nutrient-rich water by using the process of photosynthesis for their development. Because they reproduce through photosynthesis, they are called algae. Can survive in low light conditions.

blue-green algae aquarium

Cyanobacteria are very tough, it is quite difficult to fight them. For their survival, they need a minimum set of conditions, and they consume all the nutrients needed to grow and develop from water. They can survive on any substrate and quickly restore their population.

These algae can appear in fresh aquariums when the nitrogen cycle is established, and can then easily appear in the tank without supervision. When it comes to a new aquarium, it usually goes away on its own. It can often be found along the glass front of the aquarium, which gets more light.

“Cyanobacteria need nitrogen for their growth from aquarium water. This means that they will eventually use up their entire available nitrogen supply. As a result, the nitrate level in the aquarium water will tend to zero”

Get Rid Of Blue-Green Algae

  • Make sure there are no rotting food debris and other organic matter at the bottom
  • Blue-green algae may appear in new aquariums during the early stages of the nitrogen cycle
  • Use fast growing live plants to help outperform algae in resources
  • Keep the aquarium out of direct sunlight
  • Manually cleaning. Bacterial film can be easily removed by hand
  • During a water change in the aquarium (about 30%), remove the algae along with the water to be replaced.
  • Increases water circulation to prevent stagnant zones
  • Increase nitrate concentration to 20 mg/L
  • Place the treatment of problem areas on the plant or decoration with sidex, for this use a syringe and turn off the external filter to gently supply the liquid to the desired area. After a while (usually 1-2 days), the algae die, after which it must be removed
  • Blue-green algae will disappear in a clean, healthy and well-lit aquarium
  • If the blue-green algae cannot be controlled, use an antibacterial drug containing erythromycin.

Another effective way to get rid of blue-green algae is by extermination method. Since blue-green algae cannot survive without light. By darkening the aquarium completely for several days is fatal to their colony. We recommend using this method as a last resort, because if you follow the recommendations above, the growth of blue-green algae can be easily controlled.

Reduction Method To Get Rid Of Blue-Green Algae

  • Perform a 50% water change and remove as much blue-green as possible.
  • Check nitrate levels, if low add some potassium nitrate to get levels up to 20 mg / L
  • Place an air stone connected to an air compressor in the aquarium. This is necessary to aerate the water.
  • Turn off your lighting equipment and completely cover your aquarium so that no light enters the aquarium at all. Leave the tank in this state for 3-4 days. Do not worry about your fish, nothing will happen to it during this time, even considering that they will not be left without food during this period …………
  • After 3-4 days, do another 50% water change.
  • Remove the air stone
  • Check nitrate levels and make adjustments if necessary

Diatoms/Brown Algae

Diatoms (brown algae) is a unicellular algae that can appear in freshly installed tanks as a brown coating on substrates, technical equipment, plant leaves and decorations. Diatoms form the cell walls of silicon dioxide, which is extracted from water, forming a rigid “shell skeleton”. The walls of such a shell have pores through which metabolism with the external environment is carried out. Due to this method of division and the fact that hard shells impregnated with silica have little or no further growth, diatoms gradually become smaller as they reproduce.

Diatoms is usually the first to appear in newly launched aquariums. Their appearance in newly launched aquariums is considered the norm. As the aquarium matures (a nitrogen cycle is established), diatom growth decreases and becomes invisible. Diatoms can cover slow growing plants and dying leaves. If your tap water is high in silicates, it can lead to an overgrowth of diatoms.

Brown Algae aquarium

“Diatoms in the early stages of development are easily removed mechanically; they can be easily removed from the tank and aquarium decorations with an ordinary soft cloth. From the leaves of aquarium plants, they can be easily frightened. At the same time, they are especially “dusty” – if you touch such a layer of chocolate with your finger, then a cloud of dust will rise”.

Get Rid Of Diatoms

  • keep away the accumulation of organic matter in the aquarium (overdose, overdose).
  • Maintain the equilibrium of nutrients and CO2 to stimulate plant growth.
  • Diatoms usually disappear as time went.
  • In mature aquariums, the presence of diatoms indicates a severe deficiency, irregular light spectrum, or very high silicate content in the water.
  • Wipe the aquarium glass with a soft cloth to remove unwanted algae.
  • Diatoms are best consumed with otocinclus, Bristlenose Pleco catfish, Neretina Snail and Theodoxus.

Green-Dust Algae

Green Dust Algae or Protococcus is a unicellular freshwater green algae It is slippery dust on the glass of the aquarium that is easy to get rid of and does not infect plants. The appearance is due to a simple imbalance in the competition between plants and air for nutrients and sunlight. Lack of single nutrients such as nitrates or phosphates can suppress plant growth and encourage the growth of these green algae. Hours of daylight that are too long can also stimulate the growth of green algae.

Green Dust Algae aquarium

It should be recorded that Protococcus is always present in the aquarium. It is part of a well-maintained and balanced aquarium microflora. The presence of green algae plaque on well-lit aquarium glass is common

Get Rid Of Green-Dust Algae

  • Keep the light on for no more than 10 hours.
  • Use balanced nutrition.
  • Use a razor or scraper to remove algae from the glass, plastic bank cards are a good choice.
  • Maintain a constant CO2 concentration, especially in a brightly lit aquarium.
  • Protococcus is very well eaten by otocinclus, Bristlenose Pleco catfish, Neretin and theodox snails.

Another way to get rid of this type of algae is to do nothing and let them live their full life cycle. This cycle takes approximately 4 weeks. Liquid fertilizer is not needed at this time. For 4 weeks, it is not necessary to try to remove or remove, this will lead to the appearance of spores and the resumption of the life cycle. After 4 weeks, it is important to carry out a water change, reducing its level as much as possible. Then wipe the glass with a soft cloth or use a plastic bank card. pumps out dead algae residue.

If you are patient and wait for the prescribed period, you can easily get rid of Protococcus in the aquarium. Otherwise, you should always fail to clean the glass of this green dust algae.

Black Beard Algae

Black beard algae (BBA) or brush algae (Audouinella sp., Rhodochorton sp.) is one of the hardiest algae to get rid of. It is filamentous red algae of the order Compsopogon. It belongs to the division Rhodophyta of red algae. This algae consists of dark, intertwined and branched strands that eventually develop into thick, beard-like strands.

getting rid of black beard algae

With its rhizoids, it adheres very firmly to plants, driftwood, rocks, and other aquarium equipment, forming dark, velvety spots. Black Beards can also stick to filter outlets near fast flowing water streams, as well as in areas with poor water circulation. This algae also grows in both dark and light areas of the aquarium. It is very difficult to remove them from living plants and surfaces, even if it is already dead.

Generally “black beard” can be found on slow growing plants such as Cryptocorynes, Anubias, ferns. At first, small dark tufts appear on the leaves, which eventually spread to the rest of the leaves. In very severe cases, the “black beard” covers the entire contents of the aquarium with a dense carpet and at this stage it is almost impossible to remove it.

“Important information. “Black beard algae” is not a parasite because its food source is not from the internal sap of the plant”.

Reasons Of Appearance

  • Accumulation of organic matter
  • High carbonate hardness of the aquarium water
  • Strong current, contributing to a more active supply of this alga with nutrients

Get Rid Of Black Beard Algae

  • Avoid accumulation of organic matter in the aquarium (overpopulation, overfeeding)
  • Avoid unbalanced nutrition in the aquarium. Strive to maintain the following values: N (nitrate) 10-20 mg/L, P (phosphate) 0.5-2 mg/L, K (potassium) 10-20 mg/L, Ca (calcium) 10-30 mg/l., Mg (magnesium) ) 2 -5 mg/l., Fe(iron) 0.1 mg/l
  • Perform regular weekly water changes in your aquarium
  • Choose a filter that fits the volume of your aquarium (take steps to remove one strong stream of water out of it – flute nozzle, lily-pipe tube)
  • Implement measures to stimulate plant growth (supply of CO2 and liquid fertilizer), helping them compete with algae for resources.
  • Have Siamese Algae Eaters and Amano Shrimp in the aquarium
  • If this algae appears on the plant, prune off the infected leaves.
  • Plant cleaning using the “Manual Removal” method – algae is quite difficult to remove, for this you can use a toothbrush
  • Treatment of problem spots on plants or decorations with sidex, for this use a syringe and turn off the external filter to gently drain the liquid to the desired area. After some time (usually 1-2 days), the algae becomes gray or white, after which it must be removed.

Another effective way to remove black beards from infected plants is to prepare a solution consisting of 1 part white and 20 parts water, then the infected plant is placed in the prepared solution for about 2-3 minutes. After carrying out this procedure, the plant must be thoroughly rinsed under running water.

Green Spot Algae

Green spots algae form small colonies of unicellular algae of the genus Xenococcus sp. Growing on plant leaves, aquarium glass, stones and other decorations. These green spots are very difficult to remove. Slow plant growth and too long lighting can allow the xenococus to take control of the balance of the aquarium, which is highly undesirable.

green spot algae aquarium

The most common cause is often related to nutrient imbalances in the new aquarium. An imbalance can occur if a weekly water change is not performed, poor quality liquid fertilizers or a complete absence of phosphates are introduced into the aquarium. Low CO2 concentration, poor water circulation and / or too long daylight hours are also potential culprits.

“The appearance of green spot algae in the aquarium is the first indication of imbalance. If you don’t act, you could get into big trouble in your tank. ”

Get Rid Of Green Spot Algae

  • Prune plant leaves if they start to die
  • Stimulates plant growth by maintaining stable Co2 levels
  • Increase phosphate levels to stimulate plant growth
  • Green spotted algae are well consumed by otocinclus, Bristlenose Pleco catfish, neretina snails, and theodoxus well


There are many varieties of Cladophora that are grouped under the general category of algae. Cladophora appears as a branching green filamentous algae that forms green, tough, wool-like rugs and prefers to mix with the branches and leaves of aquarium plants. It adheres to glass, substrates and other hard surfaces.


Typically, Cladophora present in aquariums with stable fertilization and normal growth of aquarium plants. The most common reason for its present is poor water circulation in the aquarium and the emergence of stagnant zones in which the cladophora lives.

“The main problem of this type of algae is the maintenance condition. For its comfortable existence, the same conditions are necessary as for aquarium plants. Therefore, trying to change the conditions (fertilization mode, light mode, water changes) is useless! If plants grow – unfortunately, Cladophora also grows”.

Get Rid Of Cladophora

  • Ensure new plants are free of algae
  • Maintain the right balance of nutrients and CO2 to stimulate plant growth
  • Manual removal of algae. The best way to do this is to use a toothbrush or wand with a rough surface.
  • After removal, perform spot treatment on the problem area of the syringe. To do this, a small amount of an algicide based on glutaraldehyde is drawn into the syringe and, after turning off the external filter, the solution is slowly applied to the required place. For the complete destruction of algae, it is necessary to carry out up to 7-10 spot treatment procedures.
  • Amano Shrimp and Cherry Shrimp will graze on these algae treated areas and eat them

Staghorn Algae

STAGHORN ALGAE is red, green, white or gray algae. Its structure is very reminiscent of antlers (hence the name), it adheres to equipment, decorations and plant leaves in aquarium. Stag Horn Algae is difficult to remove manually by hand.

staghorn algae

“The flip-flop appears, as a rule, during the start-up period of the aquarium. Fun fact: If you put this algae in alcohol, it turns red”.

Reasons Of Appearance

  • Accumulation of organic matter
  • Imbalance CO2 Level
  • Poor water circulation

Get Rid Of Staghorn Algae

  • Avoid the accumulation of organic matter in the aquarium (overpopulation, overfeeding)
  • Avoid imbalance nutrients in the aquarium. Strive to maintain the following values: N (nitrate) 10-20 mg / L, P (phosphate) 0.5-2 mg / L, K (potassium) 10-20 mg / L, Ca (calcium) 10-30 mg / l., Mg (magnesium) 2-5 mg / l., Fe (iron) 0.1 mg / l
  • Perform weekly water changes in your aquarium
  • Organize the correct circulation of water in the aquarium
  • Apply measures to stimulate plant growth (supply of CO2 and liquid fertilizers), helping them compete with algae for resources.
  • Manual removal – algae is difficult to remove, you can use a toothbrush for this
  • Spot treatment of problem areas on a plant or decoration with sidex, for this use a syringe and turn off the external filter to gently supply liquid to the desired area. After some time (usually 1-2 days), the algae becomes gray or white, after which it must be removed

Another effective way to remove “staghorn” from infected plants is to prepare a solution consisting of 1 part white and 20 parts water, then the infected plant is placed in the prepared solution for about 2-3 minutes. After carrying out this procedure, the plant must be thoroughly rinsed under running water.

Water Bloom Algae

The water bloom algae is caused by the explosive growth of unicellular green planktonic algae, of which chlorella and euglena are the most common. These algae cells multiply rapidly until the water turns green. Green water algae usually have two main reasons: lighting or nutrient spikes. Over time, these algae die when the nutrients are depleted.

Water Bloom Algae in aquarium

Since the cause of algae blooms is single-celled organisms, changing the water in this case will not give the desired result. Even if you change 99% of the water, you will still have very little water with a small number of algae colonies. Because of its rapid reproduction in 2-3 days, algae water blooms will return.

Euglene is always present in the aquarium, but under normal conditions his presence is not visible. With the onset of favorable conditions for the reproduction of euglena algae, there is a sharp increase in their number. It leads to “water bloom algae”.

Get Rid Of Water Bloom Algae

  • Avoid the accumulation of organic matter in the aquarium (overpopulation, overfeeding)
  • Keep the aquarium out of direct sunlight
  • Keep the light on for no more than 10 hours
  • Green water may disappear in one to two weeks
  • Turn off the lights in the aquarium for a few days to cause a decrease in the level of these algae.
  • Ultraviolet light will kill algae and prevent them from returning
  • Using a UV sterilizer is guaranteed to kill algae. This is the fastest and most effective method that does not require additional measures. As part of comprehensive water bloom control measures, it is helpful to use finely porous filter media, such as thick sintepon. Euglena algae are well filtered on such materials. With this method, it is important to rinse the filler frequently, at least 2-3 times a day.

Thread Algae

Filamentous algae and the like consist of light green or dark green thin and long filaments. They form separate bundles in the form of long threads that attach to driftwood, stones, filter tubes and old leaves. This algae does not stick to the soil. The spread of filamentous algae occurs, as a rule, due to a strong current, when a separate thread is broken, it moves to other plants and decorations.

Thread filamentous aquarium

They grow all over the surface of the plant, entangling themselves in dense thickets of moss. They thrive in the same conditions as aquarium plants. It is a type of algae that is considered a sign of optimal conditions for plant growth.

“It is very common for filamentous plants to be present in new aquariums during the first two weeks after launch, as equilibrium in the aquarium has not been reached, the ecosystem in young aquariums is very unstable.”

A sudden burst of algae growth in an “older” aquarium can be caused by a nutrient imbalance or an increase in light intensity (usually when changing lighting fixtures). Also, the reason for the growth of filamentous algae can be a deficiency of nitrate or CO2.

Like all algae, filamentous algae develop actively when they have sufficient amounts of nutrients, and plant growth is slow.

Reasons Of Appearance

  • Too young aquarium (unsettled nitrogen cycle)
  • Intense light with unstable or low CO2
  • lack of nutrition (little NO3 and PO4)
  • high level of nitrates NO3
  • spike in ammonium NH4 concentration

Get Rid Of Thread Algae

  • Keep the light on for no more than 10 hours
  • Avoid skewing nutrients in the aquarium. Strive to maintain the following values:
  • N (nitrate) 10-20 mg / L, P (phosphate) 0.5-2 mg / L, K (potassium) 10-20 mg / L, Ca (calcium) 10-30 mg / l., Mg (magnesium) 2-5 mg / l., Fe (iron) 0.1 mg / l
  • Apply measures to stimulate plant growth (supply of CO2 and liquid fertilizers), helping them compete with algae for resources.
  • Great helpers in eating filamentous algae: Siamese Seaweed, Pecilia, Mollies, Jordanella Florida, Amano Shrimp and Cherry Shrimp
  • Mechanical removal, for this you can use a toothbrush or stick with a rough surface


A species of filamentous algae, in the early stages of development, it looks like a green fluff. Fluffy algae can appear when nitrate and phosphate deficiencies occur when the growth of aquarium plants is slow.

Oedogonium in aquarium

“After feeding balanced liquid fertilizers into the aquarium, these algae disappear after about 1 week”.

Reasons Of Appearance

  • Unstable and low CO 2
  • Lack of -macro elements

Get Rid Of Oedogonium

  • Manual algae removal
  • Maintain the correct balance of nutrients and CO 2
  • Water treatment with higher doses of liquid carbon additives based on glutaraldehyde (“Sidex”)
  • Edogonium is well eaten by Amano shrimps, Cherry shrimps, Mollies, Siamese algae eaters

Spirogyra – Silk Algae, Water Silk

Spirogyra is a filamentous green algae composed of unbranched filaments. Under favorable conditions, this algae multiplies very quickly, in the aquarium it looks like small bright green strands (sometimes very long), very slippery to the touch. Reproduction is vegetative (cell division) or sexual (conjugation).

water silk in aquarium

It is extremely difficult to deal with Spirogyra in an aquarium, since it needs the same for its growth as for aquarium plants (water rich in nutrients, carbon dioxide and good lighting). In an aquarium with good lighting, it can cover all plants and decorations in just a few days.

“An interesting fact: the algae Spirogyra got its name due to the pronounced location in each cell of one or more spirally twisted chloroplasts”.

Reasons Of Appearance

  • Accumulation of organic matter
  • Light intensity too strong
  • Too high concentration of trace elements (especially iron)

Get Rid Of Spirogyra

  • Manual algae removal
  • Try to reduce the light intensity

Another way to deal with Spirogyra. Remove as much algae as possible by hand. Removal can be done easily by gently wrapping the algae on a rough wooden stick or by brushing the overgrown areas with a toothbrush. The more of this algae you remove from the aquarium, the faster you will get rid of it.

Spirogyra is very fragile and can be easily wiped off the plants and glass of the aquarium. The erased spirogyra settles to the bottom, after which it can be siphoned off. Further, it is necessary to darken the aquarium for three days, while the supply of carbon dioxide must be turned off.

In the aquarium, daily water changes should be made at this stage. To maintain the concentration of macronutrients in the aquarium water, they must be added after each change. Sometimes there are cases when these algae disappear on their own for unknown reasons.

Another option is to try treating the aquarium with hydrogen peroxide, this option does not always work and aquarists get different results.

Fire Barbs eat spirogyra well.


This alga also has a filamentous structure. Often appears during the start-up phase of an aquarium due to an unsettled nitrogen cycle and therefore high ammonium levels. Unlike Spirogyra, Rhizoclonium does not pose a particular problem for the aquarist. And after the establishment of the nitrogen cycle in the aquarium, these algae go away.

how to get rid of Rhizoclonium algae

“There are no special methods or ways to combat this algae, since it disappears when a balance is established”

Reasons Of Appearance

  • Too young aquarium (unsettled nitrogen cycle)
  • Lack of general service
  • Low in nutrients
  • Low CO2 levels and poor water circulation

Get Rid Of Rhizoclonium

  • Wait for the balance (nitrogen cycle) to be established
  • Manual algae removal
  • Check your nutrient dosage
  • Increase CO2 levels in your aquarium


From this article, we learned about the main factors influencing the development of algae – these are the availability of: water, light, required temperature, carbon sources, minerals and organic substances. Many factors are limiting, in other words they can limit the growth of algae in the aquarium. The life of all organisms, including algae, depends on the content of the necessary substances in the environment. The degree to which a particular factor can act as a limiting factor differs for different types of algae. Algae from different departments have different requirements for macro and micro elements. In almost all freshwater and marine ecosystems, the limiting factor is the concentration of nitrate and phosphate in the water.

Light is needed for algae as a source of energy for photochemical reactions and as a regulator of development. Its excess, as well as its deficiency, can lead to serious disturbances in the development of algae. Therefore, light is also a limiting factor. For algae that live in aquatic biotopes, the movement of water plays a big role in their life. The movement of water masses provides for the entry of nutrients and the removal of algal waste products.

It is important to understand that the appearance of algae serves as a signal that your aquarium needs immediate help. There are certain measures to get rid of each type of algae. However, the choice of this or that action depends directly on the type of algae that settles in the aquarium. But it should be noted that all algae are very afraid of being disturbed. Getting rid of algae physically whenever possible is one of the most effective ways to deal with it.

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