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Bob, what is it exactly that you are hoping to "learn" by "testing" old vinyl liners? That since you didn't keel over in the time your system was running, they are good/safe thing to use?
Pliable Vinyl was a bad choice for the water treatment industry, and water delivery systems (there's a reason it was banned for use in those applications... leaching of tetrachloroethylene, a really fun chemical) and it hardly seems like such a great choice for a re-circulating food production system.
Sure, mechanically it will work for a while (as long as you get a good one...btw, fun fact: calcium levels in your water can and does apparently affect vinyls pliability), but why someone would want to use even a 'virgin' vinyl liner in AP, let alone one rubbed down with things like ethyl ketone, silk screened, and set out to bake in the sun for a while, is beyond me.
IMO (as well as the International Agency for Research on Cancer) pliable vinyl in all its forms, seems like a really poor choice for such an application. There is a reason vinyl is called "the poor mans plastic". Both mechanically, as well as chemically it is an inferior product. There are not many plasticizers commonly used that will form a co-valent bond with vinyl, which is why they will leach over time. And is why vinyl is slowly being either outright banned, or voluntarily dropped from use (by industry) in many products/applications.
Just my 2 cents. Obviously everyone is free to do for themselves and their loved ones as they see fit, but this is one issue where I'm going to choose NOT to go against the grain of what governments, industry, research and testing facilities and various international agencies are saying.
@Vlad Jovanovic - Thank you Vlad. As always I appreciate that you support your opinions with knowledge and facts.
I'm never too impressed by what government thinks is dangerous. I use a chemical product called Timbor (Disodium octaborate tetrahydrate) which is basically a borate. Our government no longer allows homeowners to purchase it which leaves copper napthenate as the next best available alternative. It's probably not real dangerous but between the two I'd rather be covered in Timbor at the end of the day. But now our government wants to ban copper napthenate which will leave consumers using even worse chemicals. So when the government says something is bad I just roll my eyes.
But when Vlad says vinyl is bad, and backs it up with a some basic chemistry I'm willing to listen.
Since Justin has already got two large rolls of new billboard vinyl it will be a tough call, but I'll be sure to pass this information on.
I LOVE TIMBOR, it saved my house.....sorry had to say that @Bob Campbell.
Bob Campbell said:
@Vlad Jovanovic - Thank you Vlad. As always I appreciate that you support your opinions with knowledge and facts.
I'm never too impressed by what government thinks is dangerous. I use a chemical product called Timbor (Disodium octaborate tetrahydrate) which is basically a borate. Our government no longer allows homeowners to purchase it which leaves copper napthenate as the next best available alternative. It's probably not real dangerous but between the two I'd rather be covered in Timbor at the end of the day. But now our government wants to ban copper napthenate which will leave consumers using even worse chemicals. So when the government says something is bad I just roll my eyes.But when Vlad says vinyl is bad, and backs it up with a some basic chemistry I'm willing to listen.
Since Justin has already got two large rolls of new billboard vinyl it will be a tough call, but I'll be sure to pass this information on.
Thank you all for the very insightful discussion, I have certainly learned a great deal. Our AP project has always been about building a safe and sustainable system. That said, it seem the difference of about 200USD in cost savings, IMO is hardly a justification for taking a chance with "who knows what the contaminant could be". Thanks again for your insights.
Jay Mottz said:
My wife and I are currently planning our second system which will be inside a greenhouse with about 100 ft2 of grow bed space. For our beds, I plan to build a frame from square steel tubing and the beds from recycled crate planks (pine). I'm considering using recycled billboard tarps instead of much more expensive EPDM pond liners. I'm interested to know if anyone has tried this and how it worked out. The site i'm looking at purchasing from is http://www.billboardtarps.com. Thanks in advance, your experience and opinions, they are appreciated!
I hear ya...sometimes they'll do some pretty silly stuff (like replace one "bad" chemical with an even worse one...seems to happen often...and in many, many fields of industry). If it makes anyone feel better, the United States Government says BP-A is A-OK. there's still no way in hell I'd use flexible PVC though...(the vinyl lined drinking water pipes, they kinda had to ban because of the whole tetrachloroethylene being a Group 2A carcinogen and all).
Now, again, I'm not saying that someone "shouldn't do this", or "should do that"...I'm a firm believer in using your own head, doing your own research and making your own decisions, Always...but vinyl does come with certain issues and controversy, some have existed for decades.... Issues that do not, thus far, exist with other materials that are available to us. I'm just saying be aware of those issues while making your decisions. That's all.
Bob Campbell said:
I'm never too impressed by what government thinks is dangerous.
I am a complete newbie to AP, but I want to recommend a great product. I did lots of research on bell siphons and even considered building my own. I found a great vendor on ebay called newearthaquaponics. I bought two autosiphons from James and am amazed by how well they work. Check it out. http://www.ebay.com/itm/271177871426?ru=http%3A%2F%2Fwww.ebay.com%2...
getting ready to build a hybrid system with NFT over media beds draining to raft culture. (Yeah, pretty adventurous but I think Sahib has proved it will work). I would love recommendations for tanks, beds, (or bed construction) and media. Right now I'm looking at either Norwesco or Rubbermaid tanks and building the media beds. Sure wish there were some agricultural overstock type containers but have had no luck finding any. Now that hydroton is gone I'm vacillating between pea gravel over 1" gravel or bringing in an expanded shale shipment. I like the idea of using the expanded shale but have not had luck finding a yard I can just buy exact amounts from. I'm in San Diego. many thanks, Paul
Beware of light getting through to all the plants when you cram NFT above the media beds or raft beds. Aquaponics is great but the plants still need plenty of good light to grow well. Make sure your NFT gets filtered water.
Pea gravel tends to be too small and definitely do the vinegar test to make sure it doesn't fizz (limestone will fizz indicating it will keep your pH too high)
1/2"-3/4" is the more desirable gravel range.
There are other suppliers of expanded clay, look into some of the Hydroponics suppliers in California for expanded clay media.
I think there is an Expanded Shale company that is in TX that probably also distributes to California. Not all expanded shale or slate is created equal so get some samples before you buy a truck load.
Keep in mind that you can do vertical gardening simply by training vines up so media beds can also do vertical gardening and they don't have the extreme temperature disadvantages of NFT pipes.
I was planning on routing the sump tank water through the NFT before going into the fish tank and then letting the media beds filter from there. I appreciate your feedback TC; I have read many of your responses and respect your opinion. I was originally thinking of hanging vertical grow towers but have read of the many issues with anaerobic zones. Of course they happen in NFT as well. Frankly I will probably try both and see what the results are. As this is an experiment and not my livelihood, (yet) I have that freedom. As we are in similar climates I was wondering what you use for heating? Obviously we both are more concerned with cooling most of the year but as I have lived in Florida I know you also have freezes as do we. Thanks and look forward to your text. PS: our gravels out here are predominantly granite. Fairly inert from what I have read. However I am leaning hard toward the expanded shale.
TCLynx said:
Beware of light getting through to all the plants when you cram NFT above the media beds or raft beds. Aquaponics is great but the plants still need plenty of good light to grow well. Make sure your NFT gets filtered water.
Pea gravel tends to be too small and definitely do the vinegar test to make sure it doesn't fizz (limestone will fizz indicating it will keep your pH too high)
1/2"-3/4" is the more desirable gravel range.
There are other suppliers of expanded clay, look into some of the Hydroponics suppliers in California for expanded clay media.
I think there is an Expanded Shale company that is in TX that probably also distributes to California. Not all expanded shale or slate is created equal so get some samples before you buy a truck load.
Keep in mind that you can do vertical gardening simply by training vines up so media beds can also do vertical gardening and they don't have the extreme temperature disadvantages of NFT pipes.
Your granite there, is it mainly crushed and squared off kind of stuff or do you have smooth rounded river pebbles too?
The larger crushed kind of granite might be fine in the lower layers of a grow bed but I understand it could be difficult for planting in on the surface. River pebbles, provided they are of a pH inert stone, are not a bad media though usually rather heavy. Granite would be heavy too. Now heavy is not ALL bad especially if you plant some tall stuff a grow bed or two for the corn, banana and Papaya could be useful.
Expanded shale or slate is likely to need some really good washing to minimize the initial pH elevation it will usually cause and to get the fines out of it but it is so much lighter that my primary gravel washer definitely chooses the expanded slate over brown river rock. The only really local gravel here though is limestone so nothing really appropriate is actually cheap here, it all has to come in by rail.
Heating. I don't. I don't raise tilapia because they would require heating to keep them alive during the cold spells here. (My first two winters doing aquaponics were the coldest on record around here and I actually had to run hot water from the washing machine tap out to the system to keep the tilapia alive those two winters and I decided I didn't want to mess with fish that would spend months not eating/providing nutrients during our best growing season for all my favorite greens and veggies AND require heating even in a greenhouse just to keep them alive.)
Through those first two winters I was also growing channel catfish. They can survive almost freezing water and they don't stop eating entirely till the water is below about 55 F (55 F being the danger zone for tilapia who stopped eating when the water got below 70 F.) So since I'm not really growing the fish for sale and as far as I can tell, the catfish and tilapia grown in aquaponics basically taste the same, both incredibly mild only major differences I noticed was I could raise a channel catfish to between 3-5 lb in 12 months while the mixed gender blue tilapia would be mostly between 8-12 ounces though I did have a few over 1 lb. I can get catfish fingerlings very easily here and I don't have to mess with trying to breed them or check their gender and they don't require heating to keep them alive and they eat through my most productive season far better than the tilapia.
Now if you are going to try to raise tomato and tilapia through winter, look into heating like the fish sweaters but for myself, I'm gonna stick with the native fish, channel catfish, bluegill and mosquito fish. Also, I don't have to mess with the conditional species permits and stuff when I stick with the natives, seeing as I'm a business I don't get to fly under the radar.
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