Home Forums Growing Spirulina Agitation Time

This topic contains 3 replies, has 3 voices, and was last updated by  Henri Lentonen 9 months, 1 week ago.

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  • #2661



    i am a newbie. thank you very much for providing information about how to grow spirulina.

    I have questions regarding agitation (i am planning to have a big tank of spirulina, so i dont think airpump is sufficient in this case):
    1. How many hours a day is the agitation?
    2. What is the best time to do the agitation?

    thank you

  • #2691

    Henri Lentonen

    Hello Paulus and welcome to the forum.

    Spirulina has been studied for long time, but there isnt so many solid rules for growing it. Best way is to research yourself and try new things!

    Usually, agitation is done with paddle wheels in commercial level.

    But you can do it manually with almost anything.

    Just remember that you dont use too much force, but agitate slowly since the spirulina filaments can break down. Also dont use too big air pump for the same reason, as also the bubbles will create shear forces, that break down the algae.

    I think best is that you use air pump and also agitate manually. When it is dark, you should let the algae rest: agitate during the daylight.

    I use air pump with timer, it is on for half hour in every couple hours. And also once or two times a day, I agitate manually with a stick.

  • #2699


    I use food grade aeration tubes weight down to the bottom with quartz. A total of 4 tubes to the bottom of each tank, with a splitter coming out from the Whisper 300 air pump that normally has 2. I leave it running 24/7 which keeps it constantly agitated. I find that it’s safe overall to leave it off up to a few hours at a time (such as in a power outage) but it starts clumping if I do that.

    I observed under the microscope that the Spirulina will move around each other to protect each other from strong light.

    I performed one test in a totally sealed container with no agitation or access to outside air and although most went bad, it started to differentiate, so it’s not like it needs agitation to survive. It’s just better for we the growers.

  • #2706

    Henri Lentonen

    The left picture is from spirulina, that is agitated manually with stick.

    The right is spirulina which has very little agitation with aeration + I manually agitate with stick.

    So only the smaller spirulina, can live when you agitate with bubbles/airpump.

    This needs more research, but it seems that even small amount of bubbles, will break down the most longest spirulina filaments.

    What I learned in my first try, was that the spirulina was shredded into pieces. I used too strong (normal aquarium air pump) for too little space.

    4 watts (normal aquarium pump) is enough for 1000 liters – but if my observation is right, you shouldnt use airpumps at all with spirulina.

    Even with a hole in the pipe so it will give just a little bubbles – the spirulina does not grow very long in that aquarium – compared to the left picture, where longer filaments are present.

    Image of the aquariums

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