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This topic contains 8 replies, has 5 voices, and was last updated by  alexshull 1 year ago.

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  • #1070



    I have a start up that can make all kinds of heat sealed parts up to 38 x 58″. I have been experimenting with algae grown in bags for the last several months. Here is a photo of my latest iteration with some culture happily growing inside of it. If you are interested in me making one for you let me know. If you have a custom design you’d like to try out, let me know as well.

    You can see some of the stuff we have made at http://www.expandable-structures.com


    This the PBR I printed.

    • This topic was modified 2 years, 7 months ago by  mdrever. Reason: Added picture
  • #1072


    Hey – that looks pretty cool. Is the plastic non leaching? What is it made of? Do you have bubbles in the plastic? How do you move the spirulina around?

    How much does it costs?

  • #1073

    Dr Cath

    It does look very cool, thank you for sharing. I’d love to know more about it. In addition to Martin’s comments, I’d like to know what your system yields? Is it possible to warm up the culture medium for spirulina growers that live in cooler areas?

    How do you add nutrients to the system? And how easy is it to harvest? A video would be great!


  • #1077



    The plastic I used is food grade polyethylene. I don’t know what you mean about bubbles in the plastic. If you are asking about aeration, I put in a separate line as the spirulina like to clog the aeration lines and I’ve had to pull it to clean it. I don’t really move the spirulina, I have bubbles coming from the bottom and that tends to move them around, plus the aquarium pump is mounted directly to the bag, so it agitates the spirulina a little bit.


    Honestly I am just getting started. I’m planning on harvesting my first batch in the morning. As for heating something up for cooler climate, I’d imagine so. A patch heater or a rope heater in the bag would help. And there are coatings that can be applied to the plastic to minimize thermal losses. My plan for adding nutrients is related to harvesting. When I drain the bag, I plan on filtering out the spirulina, Then I’ll add back what ever growth medium is needed to top off the bag and I’ll add some replacement nutrients at that time.

    As for Martin’s question about cost, that is a tricky one.

    The process that I used to make this is a novel process that is great for prototypes, but not for production. In a production environment you would have to make thousands of them to get the cost to under ten dollars a bag. That would involve tooling that would cost at least $5-7k, materials and labor. If you designed it correctly, then you are in luck, you have a bunch of very affordable bags. But if your design didn’t work very well, you are out a bunch of money. That is the problem I am trying to address. I can make a single prototype of the same quality as a production part, but for much lower total cost. So this bag would cost around $200, which is much cheaper than over $5k. I want to help researchers, product designers, engineers and others that want to iterate with their heat sealed designs, so they don’t make costly mistakes. It is similar to 3D printing, but for heat sealed parts.

    If you want to have the design file I used to make it I can post it. I work with vector files, such as adobe illustrator, inkscape, coreldraw, etc. You can take the design modify it, or create your own, if you’d like.

    Let me know if you have any other questions.


  • #1078


    So I harvested. I am learning about how to take better notes. The PBR had a volume of about 2.5 gallons of growth medium that yielded 3 oz of spirulina in about a week or a week and a half. The date dither is due to the fact that I pulled the culture from the PBR because and parked it in a translucent container until I figured out what was wrong. The observed characteristics were extreme clumping at the bottom of the bag, while maintaining a great blue green color.

    I harvested and divided the remaining medium between two bags and back filled equal parts of reserve culture and I am going for round two. I have some nutrients that I am going to put in the PBRs in the AM, but thus far in my quasi-scientific opinion, I think I got six times the growth rate than I expected, compared to aquarium results.

    • This reply was modified 2 years, 7 months ago by  mdrever.
    • #1804

      Dr Cath

      Hi Mike,

      How is your production doing? It’s been over a year now and I’m curious if you made any progressed / changes in the design of the bags.

      What is your production today. It’s usually measured as weight of dry spirulina per surface area.
      Have you dried your harvest or do you eat the spirulina fresh?

      Do you have any additional pictures?

    • #2522


      This is a neat idea. Are you still working on it? Can I buy a prototype version from you?

  • #1141


    Very interesting. I love new ways of growing spirulina! And this is a neat one. Congrats!
    Power to spirulina lovers <3

  • #1202


    Greetings, Y’all,

    Using direct sunlight for me now is not possible; I am trying to set up a 10 gallon aquarium using lights only. I plan on using the usual lights for fish aquariums on top plus reflective foil on the back, the bottom, and the two small sides, with the “front” unobstructed. Just this added reflective foil I calculate to increase the amount of light by 4 times.

    In the front of the “front” outside of the aquarium would be five 26 watt CFLs, which can be very bright. The CFLs are 2700K, kinda warm, good for spirulina. Just these five 26 watt CFLs are really bright. I fear that they may be too bright.

    I will probably need a heater floating in the mixture in insure 93 degrees F. water. I am not sure that I will be able to buy such a heater since most aquariums are for fish and not for spirulina. I am hoping that the light will help keep the water up to 93 degrees F. My basement where it will be situated is like sort of cold, from 66 to 72. I could enclose all of the lights partially or fully and this would probably bring the water temperature up.

    I live near Pikes Peak and we have some seriously wholesome spring water in Manitou Springs, Colorado. This spring water, depending upon the spring, is free and is loaded with minerals of various kinds, depending upon the spring.

    Why could I not just be able to use this free spring water along with sodium bicarbonate, pee, and a good pH meter in which to raise my spirulina-buddies?

    Any thoughts would be appreciated. This is not just a hobby for me. This is a matter of health or ill-health for me.


    Roger Bird, aka bachcole

    Colorado Springs, Colorado

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