Trough Liner And Construction
The original liner material for the troughs that we used in our first systems in 2007 (which is already approved for organic certification by Oregon Tilth) is a 23-mil, 3-layer, 15-year laminated LDPE material made by Inland Plastics, Ltd., in Chicago, called P2000. Their phone # is 815-933-3500, or 800-387-7765. Unfortunately, this liner only comes in 750-foot rolls 12 feet wide, which weigh about 800 lbs. each and cost about $3,500 with shipping. Oregon Tilth certified our systems organic with THIS LINER, and Organic Certifiers has certified both this liner and the one in the following paragraph. Be certain your certifying agency has approved the liner you intend to use before you buy a huge useless roll of it and then find you can’t get certified.
A liner we like better, AND have been using for all our new systems for the last seven years is Dura-Skrim R20WW by Raven Industries (www.dura-skrim.com, PO Box 5107, Sioux Falls, SD 57117-5107). This is a tough, 20-mil laminated LDPE plastic film that comes in 6-foot-wide rolls, and seems to perform better than the P2000.
Your contact for large orders (over 500 linear feet), is Courtney Mendelson, Account Sales Service Representative, Raven Industries – Engineered Films Division, Phone: 800-635-3456, Fax: (605) 331-0333.). Don’t bother her for orders smaller than 500 lineal feet, please! (info next).
Purchase smaller orders from: Randy Campbell, 256-679=9488; rancam@hughes.net, AND Global Plastics (http://www.globalplasticsheeting.com/aquaponics-plastic-film/, AND from IWT CargoGuard: http://iwtcargoguard.com/, 609-971-8810.
Great information, thank you so much!!! What do you use for bulkhead fittings? Everything that I can find have EDPM gaskets and as I understand it EDPM is not allowed in organic production and possibly poisonous anyway. Thanks in advance!!
*EPDM. Oops!
Thanks Jess.
I understand the importance of the liner material being food grade and I have researched that.
I can get food grade liner but it’s black. 🙂
I’m just wondering if there are any specific reasons for yours being white, other than that being the color available when you searched for the right material. I also think it looks very nice, and allows you to easily see how much algae growth and bottom silth is in the trough etc, but I’m not interested in paying extra to import a white liner if the black one will do the job.
I’ve seen many troughs built with black liner.
– Jens
It’s useful here to make a distinction: no one cares if your liner is food-grade or not but you. And “food-grade” is NOT a certification that is given to the liners, regardless of what the salesman says.
The ONLY “food-grade” certification that exists in the US is given by the NSF- the National Sanitation Foundation; and you can find it on the bottom of plastic items such as bins and Husky garbage cans that also approved for use in processing food for humans. These items are marked “NSF” in big letters; it’s easy to tell if such an item is food-safe or not because of this. They don’t certify this liner material, TBMK.
What is more useful when talking about liners is to know what kind of plastic the liner is made from; here again, “white” or “black” is absolutely meaningless in terms of knowing whether the plastic the liner is made from is toxic or non-toxic; because almost all plastics (both the toxic ones and the non-toxic ones) are available in both colors.
If the liner is made from HDPE (High Density PolyEthylene), or LDPE (Low Density PolyEthylene) it is almost always organically certifiable, and therefore what you mean when you say “food safe”. Liner material of NSF-grade PVC, which is also known as “food-grade vinyl”, is also organically certifiable and “safe”.
As Jessica wrote, liners that are made from Hypalon, EPDM, and Neoprene (which are all OFTEN black!) are NOT organically certifiable, and are potentially toxic to your fish, plants, and you!
If you’re planning on getting organically certified, you’d better get your liner approved by your certification agency before you buy a $12,000 roll of it and find out you can’t use it in an organically certifiable system!
Just my two cents based on what I know of organic and industrial chemistry, and the USDA organic certification process (we were the first in the world to get an aquaponics system certified organic in 2008).
Aloha, Tim…………..
Tim,
That’s also what I’ve learned from my research into the different plastics. I mean in regards to the characteristics of the different types.
Things are a little different here regarding certification etc. For any food application the products must be of food safe grade, so all products in that category can be used in organic production as well. There is no actual certification of plastics, but the manufacturer must declare that the product lives up to the norms stipulated by the food safety regulations. You can then be asked to provide proof of which products you are using and their declaration of compliance.
Here the organic certification authorities focus on the absence of chemical fertilizers, pesticides and herbicides, cleaning agents etc. Of course the fish feed must be organic certified as well.
Basically you must produce a document describing all aspects of your production, products used, routines etc. Based on that you receive your certification and then you will receive unscheduled control inspections.
I want to thank you for all the knowledge you share thru your blog. This is allowing me to start up on a shoestring and learn the basics before I get into the deep end.
When I’m ready to go commercial I will buy your package for sure. Like you say, no-one else offers your level of experience from their own business. I always believe only in those who have results to show.
Where can I find black foodgrade liners please. Thanks in advance.
You can get the same product from Raven Industries that we use for trough liner, their R20WW, which is a double-sided white 20-mil thick LDPE liner that’s been approved by the certification agencies.
The same company has a 12-mil LDPE liner that’s black on one side and white on the other; and we tested that and found it worked as well as the 20-mil (with the white side towards the rafts, the black side down), but were a little wary of it being thinner= maybe not as much puncture resistance. But it worked fine.
We have no idea what would be different, ie how plants would grow, and so on, if you put the black side up.
With Warm Aloha, Tim
Hi guys,
I’m having a hard time finding white liner.
Everything here is black.
Any reasons I shouldn’t go with the black liner?
I’m planning a tunnel greenhouse setup.
– Jens
I’m located in Denmark buy the way…
🙂
– Jens
Hi Jens,
The reason to use the Dura-Skrim liner is because it is a food grade liner. That is important since you want to eat what you produce in the system. I am not sure if there is a supplier in Denmark but they may have European distributors… I would call Raven Industries, their toll free number is +1 (800) 635-3456.
You do not want to use hypalon, EPDM, or neoprene rubber liners because they are not designed for food-grade applications, and may be anywhere from mildly to quite toxic to your fish and plants. Most of the black pond liners are in that category too- they are ok for a hobby pond but not ok if you want to eat the fish or plants. Swimming pool liner is the worst since they usually spray it with herbicides to retard algae growth so definitely don’t use that.
Hopefully that helps,
-Jess