Backyard Aquaponics
A place to discuss aquaponics

The two layers of poly are usually clamped in brackets or rolled on long pieces of wood.
At my work (organic greenhouse in Calgary, Alberta Canada) we utilize the air filled dual layer system.
Keep in mind that it is OUTSIDE air that is blown in. The humid inside air would cause condensation and freezing problems (in subzero climates).

Basically one needs a blower that will spread the poly layer sufficiently. Not so much that it is drum tight, which accelerates wear, while also tight enough that wind doesn't cause excessive flapping.

cool, the ones i have seen blow air from inside, but it certainly wasn't sub zero conditions

If you blow in outside air, wouldn't that make the double layered greenhouse material pointless... The purpose of the double layer is to trap air in between the layers because air is a better insulator than the plastic. Pumping the outside air in which is colder would cause the greenhouse to lose heat... as adjacent temperatures try to equalize.

IMHO pumping air in the gaps doesn't really make sense to me as it is causing more movement of air over the expose surfaces, regardless of whether it is cold or warm air. Like blowing air over a hot or cold surface it changes the temperature...

like i said, the ones i've seen are not a "flow through" they simply keep the gap inbetween the films pressurised, picture a small fan blowing into a plastic bag, it will inflate the bag and keep it pressurised, there won't be any flow as such.

raimiuso
being in Alberta, do you know Dr. Savidov in Brooks, AB at 'Crop Diversification Center? He is doing aquaponics development at his facility and at Lethbridge Community College. Also, Eric Hutchings in the AB government located in Lethbridge is involved. Both are excellent people with much knowledge and experience. Let me know if you need e-mail addresses or an introduction. Seems like a great contact right in your own province. I was visiting in August and was shown great hospitality and learned a lot. They very much like to work with and support private enterprise in Alberta. I hope you either know them or get to know them.

I have tried calling Dr. Nick Savidov and left a message, recieving no response. If you can help facilitate introductions that would be great.

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Very little outside air actually flows through the layers of poly, as Steve said, its just to hold the pressure up from the small leaks that occur. This does not result in large air movement.

raimiuso
Please give me your name and some contact info (phone & e-mail) to my email dbasberg@dsbengg.com. Dr. Savidov has been out on medical leave and he does not respond as quickly as he used to. I hope he will be well soon and back to work. I think he is a great guy and very knowledgable about practical aquaponics. He wants it to develop into a large commercial enterprise. I will be glad to email an introduction for you when I get your reply with some info. If you would, I would like to know about what you are doing too. If you go to my profile, you will find my posts that talk some about what I am doing. Another good contact is Eric Hutching in Lethbridge, AB. His work is coordinated with Dr. Savidov's efforts.