Polystyrene floats in DWC

[Josie]

I love Aquaponics but have yet to start my own set up. I'm still trying to fill in my knowledge gaps.

I am concerned about Styrene leaching into food from Polystyrene floats used in DWC, Anyone know anything that will stop me being concerned? Everyone seems to think it's only a matter of time before Aquaponically grown food is classed as organic but this will not be the case for DWC using Polystyrene floats.

Hope someone Knows more than me (should be easy!)

 

 

 

[Vlad Jovanovic]

Thanks Jon. If I could mix the two, and get them to blend together without some crappy negative reactions that would be good enough for me I guess.

[TCLynx]

Vlad, perhaps you don't have to paint the rafts.  Inside a greenhouse you don't have to worry about wind blowing it off, perhaps you just make a cover for your raft from a piece of liner? 

I've not painted any of my rafts because I've been using them as wicking rafts for starting seedlings and they are covered by wicking mat or capillary matting.

[Vlad Jovanovic]

That might be a idea. Guess I would have to find a suitable and economical material...then cut all those holes out. Yikes! Might be time to hold a "workshop" 

[Damon Polta]

vlad, you mentioned in another thread about needing some questions answered about the DOW boards. i'll answer what i can.

[Vlad Jovanovic]

Hi Damon,

Basically I was just wondering if during your time there you ever had the chance to discuss, or if the topic ever came up, about why FAP does not advocate the use of the polyisocyanurate boards? Beyond the reference of polyisocyanurate (or polyisoisocyanate I think they confused the two because I don't believe polyisoisocyanate is even actually used in the manufacturing of poly-iso rigid foam insulation boards...polyisocyanurate however is)

sounding like or being related to cyanide, (which in a way it kind of is, but so is a lump of coal and a diamond...yet totally different properties) and the anecdotal 10% mystery fish kill. The only scenario I've been able to find in which hydrogen cyanide might be released, is if the board catches fire. But any foam board weather poly-iso or ploystyrene is going to release toxins in that scenario. The oils I'm not sure of. So I was wondering if it ever came up...anything more detailed?

Many poly-iso boards contain a flame retardant as well, though different from the ones used in ploystyrene. The most common flame retardant being used seems to be trischloropropylphosphate (TCPP), in which the chlorine and phosphorous are the active fire-retarding components. This chemical is suspected of being a bio-accumulative toxin as well, but so far as far as I can tell this has not been proven. So it may still be a good idea to stay away from the ploy-iso boards (those are the ones that often have a foil backing) if your particular manufacturer uses a flame retardant. I've seen some photos here where people do use them. I don't, and wont but maybe this info will help someone to make a better informed choice about some of these materials if they care about that sort of thing.

At any rate it turns out that FAP did us all a big favor...

Sorry about the italics...

[Damon Polta]

wow, tons of awesomely big words.

to easily simplify things im going to use words that are a bit easier to understand.

although i do under stand how different coal is from diamond, the difference between cyanid and polyisocyanurate (pink boards are the most common of this type) is a bit smaller. we fielded many questions about system failure and the root cause was the use of the pink boards. people made the choice to use them because they are cheaper. once they switched out the pink boards for the blue boards, things started going the way they were supposed to, after a total system sterilization of course.

it's not just the flame retardant we need to be worrying about... im thinking the adhesive that holds on the foil backing, and  in some cases the heat treatments that hold it on, are what's toxic rather than the foam board themselves. it also might be the difference between chlorofluorocarbons and other blowing agents in the production process. 

i do know that there are two types of DOW blueboards, the indoor, which goes in between wall studs, and the outdoor, which normally lines cinderblock basement walls from the outside. since the outdoor boards are in fact outdoors, they meet a stricter requirement as to what go into them since they are in direct contact with the outside world... although i have used the indoor variety, you can tell the difference because 1.) they are labeled indoor use, and 2.) they are scored ever 18" which is the standard width of wall studs... makes them easier to install into the walls when you dont have to cut them... you can just karati chop them at the score lines... it's pretty fun actually... so not only at the outdoor blueboards more structurally sound because they lack the weak points of being scored for fracturing, but they are more environmentally safe.

now all boards are subject to sunlight degradation, causing them to become brittle and flake apart, and of course that's not good for the fish if they eat the flakes or the flake get into their gills... but coating the tops of the rafts in a non-toxic paint that meets the MSDS requirements for our aquatic friends, will prevent sun damage.

[Vlad Jovanovic]

Yeah, I agree. We could stand to get rid of some of those imposing sounding names...but lets not do it by colour as that may just confuse things further since there are many companies around the world that make extruded polystyrene boards in the colour pink (some with, and some without the bromine flame retardants)...Could we just call them 'poly-iso' boards or even foil-back boards to distinguish them? Or hey, how 'bout pink/poly-iso'? Just a suggestion...

Ok, so it definitely was not just one incident that that led FAP to direct us away from the poly-iso/pink boards, and the fish kills didn't seem to be (to the best of your knowledge) related to other typical water quality parameters that could result in such a death of fish? If you are say that's the case Damon, that's good enough for me...

Yeah, who knows...adhesives, flame retardants, blowing agents, the foil itself... either way, it would sure seem like a good idea for people to fork over the extra bucks for the Dow blue board. (Or at least something with the same or similar formulation).

It seems most of the companies (decent ones) have stopped using CFC's as a blowing agent for poly-iso/pink boards and have switched to pentane. Which might be good for the environment, but like you alluded to, might not be all milk and cookies in an AP system...

(A side note on extruded polystyrene blowing agents... The blowing agent that was supposed to save us from the ozone depleting CFC's turned out to be worse for the ozone/environment that the CFC's themselves were. They have now (in the E.U for sure and perhaps parts of the US?) been phased out (or in some cases are still being phased out) and being replaced with HFO-1234ze (under the name Solstice)...who's environmental impact has yet to be determined. Hope it works out better this time around)...

As far as paint goes, were you able to notice any sloughing off after time, of the Bright-White-Exterior-Latex paint? I take it, it held up fine in the hot Hawaiian sun (while you were of coarse)? Any tips you can think of relating to paint or painting? 

[Damon Polta]

yeah, might not be good to just color code things... it's just around where im at you mainly have 2 options, the dow blue, or the pink panther.

i always direct people to the MSDS, and then for further info the manufacturer... but in some cases as we just saw, not all things help, so the third step should always be see the help of someone that has gone through what you're trying to figure out.

when it comes to the paint it acts like the paint on the cars by what i've seen. the edged chip due to jostling with the trough walls and other rafts, but that about it. there is a problem with a point of impact... saw you drop a tool or something on the raft... then it will peel away from that area as well... just like denting a car. if that happens just peel away whats freely hanging from the raft and touchup the spot with more paint. it'll seal the hole and keep the problem from getting bigger...

we've even repaired broken rafts. we used fiber glass epoxy down the broken edge and pasted them together. then, we used shiskabab skewers and laid them perpendicular to the crack, then adhered them to the top of the painted side with fiberglass epoxy to reenforce the bonded area... worked like a charm.

i'd do the paint job after the holes are drilled though. painting first them drilling just chews up the paint job and you have to retouch all of the edges of the holes... it's senseless extra work. plot, drill, then paint. 

one thin we've always wondered is if different colored system safe paint would effect the growth of the plants... we only used white on the friendly aquaponics, because that's all we bought i guess... but i've always wondered if the different colored paints would attract different amounts of the light spectrum to the area, or reflect some back out and absorb some to not be reflected if that would have any noticeable effects on the plants... just some food for thought...

[TCLynx]

You could always place some of those red plastic tomato mulch things under some tomato plants in rafts to see if it makes a difference or not?

[Damon Polta]

im thinking you'd need a fairly large trough system to try this... the variable controls being feed input, evenly distributed nutrient levels, even distributed D.O. levels, and consistent flow rate. after those are under control you'd want to separate the colored rafts by having a white buffer raft in between each differently colored raft as to not mess with or react to the different kinds of reflected or absorbed light...

the reasons it'd have to be all in one system would be to ensure that all controllable variables would be the same.

really im thinking shining different filters of light onto the plants would show more of an effect than the absorption or reflection of light, but i'm an efficiency nut, and if there is any chance of an increase in production i'm always looking for the edge over the competition if it's plausible, and cost effective.

there's 3 main differences in the color white... red white, yellow white, and blue white... yellow white paint is cheep, but looks dingy... the blue white is the kind of white used in doctors offices to make the room seem brighter, it's a bit more expensive, but it looks worlds better... it absorbs the darker colors and reflects the brighter ones back. so if the extra brightness would have any effect on the growing of plants, especially in a limited light environment, the reflection of light would be pretty important when your main light source isn't direct sunlight... think of plants in the office space not sitting right under the window that still grow, though at a slower rate.

even if the color of the rafts does effect the growth rate, even on a small scale... if it all costs the same i figure why not right?

[David]

Hey folks,

 

I'm a little late in getting here but thought I would add my two cents regarding Dow blue vs Owens Corning pink.

A couple months ago I was debating setting up DWC tables to start growing "Black Seeded Simpson" lettuce, a summer variety here in Texas.  I had a 250 test system with 16 cubic feet ebb & flow.  I looked up the MSDS on Owens Corning XPS and gave it a good study.  It actually says "safe for fish and animals"?  So I got a piece and cutout a 1square foot raft and proceeded with my test.  The system was stable for months and producing like a beast even in partial sun.

Well about a week or so after adding the pink raft I experienced an immediate 10% fish kill.  I was like wtf?!  I removed the dead,tested waters,coppers etcetc.  Nothing was wrong.  Next day two more kills.  The next two more.  I ended uplosing about 75% load of fish in this system before I was finally able to stabilize it by direct salting to 4ppt and water changes. Most of the plants died but I was able to top and clone the other 50%.  It wasnt until I realized that removing the 1 cubic foot raft did the remaining fish start to recover.  They contracted Ich disease during this trial.  well I could go on but this was the main point of NOT using Owens Corning XPS.

[David]

Lost the cursor on my last reply so I will continue here....

I spoke with a Dow trained guy at the local hardware store yesterday.  He was extremely familiar with the method employed with makimg fire resistant insulating sheathing.  He informed me that those bromine/bromide chemical used to make Owens Cornimg XPS, Insulfoam and I believe R-Tek have no known antidote on this planet.  So if you decide to use it I hope your are one with your God. That is why they ONLY carry the Dow blue board.  

David said:

Hey folks,

 

I'm a little late in getting here but thought I would add my two cents regarding Dow blue vs Owens Corning pink.

A couple months ago I was debating setting up DWC tables to start growing "Black Seeded Simpson" lettuce, a summer variety here in Texas.  I had a 250 test system with 16 cubic feet ebb & flow.  I looked up the MSDS on Owens Corning XPS and gave it a good study.  It actually says "safe for fish and animals"?  So I got a piece and cutout a 1square foot raft and proceeded with my test.  The system was stable for months and producing like a beast even in partial sun.

Well about a week or so after adding the pink raft I experienced an immediate 10% fish kill.  I was like wtf?!  I removed the dead,tested waters,coppers etcetc.  Nothing was wrong.  Next day two more kills.  The next two more.  I ended uplosing about 75% load of fish in this system before I was finally able to stabilize it by direct salting to 4ppt and water changes. Most of the plants died but I was able to top and clone the other 50%.  It wasnt until I realized that removing the 1 cubic foot raft did the remaining fish start to recover.  They contracted Ich disease during this trial.  well I could go on but this was the main point of NOT using Owens Corning XPS.