How to get Rid of Green Water Algae


Green water algae is less common but a very consistent algae, if not taken care of properly you will never get rid of it and it keeps coming back no matter how many water changes you do. The reason ? With each water change you provide more nutrients for the algae hence accelerating its growth further.


The reason for Green Water Algae ?

The reasons for any algae is due to the unbalance of the tank specially in planted aquarium where as freshwater tanks can also face similar issues if:

1. The aquarium is exposed to sunlight. (Direct or indirect)

2. The aquarium is not balanced (In case of planted aquarium).

3. The lights are on for too long.

4. The algae is introduced via external source (example fish plants bought from a source which has or had green algae in the aquarium).



How do I eliminate Green Water Algae ?

Follow the steps below to get rid of the algae:


Day 1

  1. Install a UV steriliser.
  2. Switch off all lights and cover the aquarium with any opaque cloth or paper so that does not allow the light to penetrate. Make sure all other equipments are running
  3. Change 50-70% water.


We do a water change at this stage to reduce the amount of build up algae in water column, and since you have covered your aquarium and installed a UV the algae will not accelerate any further as it has no source to grow.


Green water algae planted aquarium after

Day 3
4. Remove the cloth and change 50% water. Let the UV run for another month until the algae completely disappears.
5. Do not overfeed your fishes during this period specially as it will act as a promoter to the algae.
6. Change light timing to minimal 3-4 hours a day.  


Important points:

1. Do not feed the fishes or look inside during this period from Day 1 to Day 3.

2. If you still see lot of algae then let it stay covered for another day or 2.

3. For the ultimate and permanent solution you have to change the location of the aquarium or install a UV steriliser permanently, there are occasions where its not possible to change the location hence I am giving another option.

4. Cover the place from where sunlight reaches your aquarium, for direct sunlight there is no solution and the algae will keep coming back.


- Kshitij Gupta 



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