Green Water in Fish Tank – Causes and Cures

When we put a bucket of water in the sun all the time, a week later we go back to see that bucket of water, will find that the bucket of water is completely green, and almost can not see the bottom of the bucket. What is this? Some people may think that the water is moldy and spoiled this is also a frequent problem in aquariums – green water. Green water develops quickly, often one day long can make the water in the aquarium all green.

What is green water?

The main cause of green water is the crazy growth of various single-celled green algae, such as Chlorella, Chlamydomonas, etc. Among them, Chlorella accounts for the majority, and it can be said that Chlorella is the culprit of green water.

There are two types of algae, one is called attached algae and the other is called planktonic algae. Although they are both algae, the way they grow is very different. The growth of algae needs to be attached to something, such as a tank wall, sunken wood, rock, or sand. As long as they can see the sunlight and are in the water, they will grow. But planktonic algae are different, they are like wanderers, floating around in the water, and will not make the water clear by settling. The cause of green water comes from the planktonic algae, Chlorella, and single-celled algae.

Generally, the formation of green water is in the sun temperature, and other conditions to have the right situation, so as long as you take the water to the sun, and provide sufficient oxygen and certain nutrients, a tank of clear and bright water will become the world of chlorella, which shows that chlorella is dependent on sunlight growth and reproduction, in the sun can make them multiply and grow quickly.

Chlorella and green water

The main component of green water is Chlorella, commonly known as green algae, an organism that has been reproducing on the earth since 540 million years ago. It is a single-celled green micro-algae, no matter the huge changes in ecology or natural disasters have not been able to destroy it, and its stable genes have always remained unchanged. This organism was called Chlorella, until humans invented the microscope more than a hundred years ago, because its diameter is only 3 to 8 microns, you must use the microscope more than 600 times to see, and the shape is rounded. And the green water that often appears in fish tanks is Chlorella.

Chlorella is an efficient photosynthetic plant that grows and reproduces by photosynthesis. Chlorella can stabilize and purify water, and absorb and transform toxic substances, which is beneficial for fish tanks, but because many fish lovers feel that it is an obstacle to ornamental, so they are actively removing green water. The algae are constantly transforming the sun’s energy, which is containing many nutrients and releasing large amounts of oxygen during proliferation; and its photosynthetic capacity is more than 10 times higher than other plants.
green water fish

What caused the green water outbreak?

1. Sunlight or light exposure

Whether it is sunlight or light, as long as there is light, it will provide conditions for algae to grow. In general, a dragon tank is rarely exposed to direct sunlight, but the light can’t be avoided, and the algae will spread like crazy.

2. Water is too fat or too much organic matter

Fish residual feces, fed fish feed, and various organic impurities left in the tank will provide more nutrients for the growth of various algae.

3. Fish tank water falls acid

Most of the aquatic plants are more suitable for reproduction in acidic water, too much organic matter, and aquatic plants grow vigorously, chlorella flooding, etc., and will, in turn, make the waterfall acid, this water environment is most suitable for the Chlorella outbreak.

How do prevent green water outbreaks?

1. Reduce the length of light

The environment that can produce green water is usually very good light, maybe too much sunlight, or maybe the tank light is on for too long, so the time of photosynthesis of chlorella becomes longer.

Since we know that Chlorella is dependent on light, we will treat the problem by reducing the light. You can place the fish tank in a poor light environment, if there are aquatic plants inside the tank, then we will take the measure to turn on the light to ensure they grow well. But don’t turn on the light for too long, don’t exceed 10 hours a day, it is easy to grow algae, not only Chlorella but also other algae.

2. Maintain proper water change frequency

Water change is the fastest way to improve the aquarium, but the frequency of water change should be mastered. Neither too diligent nor too lazy, according to the specific circumstances of the specific operation. There is no way to specify this because everyone’s tank is different, you need to master your water change rhythm.

3. Biofiltration

Biological filtration is relatively slow, troublesome, and a big project. The principle of biological filtration is generally to raise some organisms in the water to feed through filtration, such as those stream clams, and mussels. Or can rely on both filtration feeding and mouthpiece feeding snails. These organisms are not easy to get rid of the green water, and it is not easy to keep them in a bare tank. This method is only suitable for players who have bottom sand.

It is recommended to find a clean cloth with coarse fiber, put this cloth on the top layer of the filter, then turn on the flow rate of the filter to the maximum and let it work. Filter to the whole cloth has turned green after taking it out and washing it, and then put it back for filtering, and so on, dirty wash, wash and put. After a few hours, the water will slowly become clear. After testing this method is good and does not affect the nitrifying bacteria system.

4. Proper feeding

If you feed too much bait in the tank, but the fish neither eat it all, and you do not fish out in time, then the softened bait will not only pollute the water but also easily lead to aquarium eutrophication. Water eutrophication is also the main reason for the formation of green water notes. You can appropriately reduce the amount of feeding, the fish can not finish the food, and should be immediately fished out to prevent them from polluting the water quality.
green water tank

How do get rid of green water in fish tanks?

1. Germicidal lamp

Put in the filter inside the water flow is slow, can not directly irradiate the fish, and do not stare with the eyes for too long. Because the UV itself is harmful to the human body, especially at close range. So it is recommended to observe when the light is turned off. If there is a bottom filter conditions, it is recommended to put in the last frame, so that the nitrite produced into the anti-air lift and be turned into nitrate, of course, building a separate sterilization box is best, especially for algae to play the role of seconds.

It is worth noting that: UV germicidal lamps can destroy biological DNA, and both sterilization and algae can be eliminated, which can be used to eliminate chlorella in the water. Generally speaking, about three days of green water can disappear. But the germicidal lamp will also kill the beneficial bacteria in the water, so it should be used with caution.

2. Biological control

Use algae-loving Daphnia to eat the chlorella. But Daphnia is usually the food of fish, so it is only suitable for planted aquariums without fish.

3. Salinity control

Chlorella is a narrow salinity organism, very sensitive to the increase of salinity, so adding salt to the water is very helpful to eliminate the green water.

4. Inhibit the growth

Sunlight is the prerequisite for photosynthesis of Chlorella, so the growth of Chlorella can be inhibited by reducing light, reducing feeding, and strengthening water changes, and it is safer. The disadvantage is that it will take a longer time.

5. Algaecide

Although the effect of algaecide is obvious but will produce harm to fish and aquatic plants, and generally do not recommend the use.

The problem of green water in the fish tanks may appear in all stages of fish keeping, pure green water is caused by a Chlorella outbreak, but there will not be only one kind of algae in a fish tank, a single race outbreak will affect the original balanced system, and consume oxygen in water rapidly. So for fish tank green water, we can not be completely at ease, need to maintain some vigilance.

Comments (2)

  1. The water in my fishtank stays green, must I replace all the water and clean the tank?

    Hennie Maartens
    Apr 20, 2023 Reply
    • Hi Hennie Maartens, you can change 1/3 water every 3 days and open the UV light to kill the green water with the hygger 032 fish tank filter pump, which can purify green water and create healthy water. Generally, it will take one week to kill the green water. Hopes it is helpful.

      hygger team

      Apr 21, 2023 Reply

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