PT wood ???

[kneedeepinwater]

Hello, I hope all is well for everyone.

I am interested in building DWC rafts with tables above them to sit cut IBC totes on top of. First do you think the lettuce growing in the raft would get enough light(outside in greenhouse)? Also if I were to try get certified organic in the future would the 4x4 post used as legs for supporting the tables above the rafts cause issues?

If they were to cause issues with becoming certified organic what about using square steel to support the tables and brace the sides of the rafts?

Thanks

[urbanfarmer]

Someone on here has stated a story of a friend who had issues using PT wood above the vegetable area causing a problem. I don't remember the specifics as I don't think any were given since it was a friend of a friend kind of thing...

It may be good to call your local certifying agency. Depending if the PT uses the old arsenic or the new copper to treat the wood may make a huge difference as to whether it has an impact on the organic certification process... maybe not... but just a thought.

[kneedeepinwater]

Yeah I read that also but I think they said his greenhouse was built out of PT wood. I wouldn't suspect any water should be getting on the pt wood to drip on the plants in the raft system unless i had leaks. What do you think?

Do you think I should just use coated square steel tubes for the legs? Do you think the lettuce in the raft system would get enough light from the sides to with the ibc totes 2ft or so above?

Also what size sump would you recommend for 54 ibc totes and a 40x4 growbed? I was coming up with something around 4-5000 gallons which includes a little extra room?



Thanks

[urbanfarmer]

I really don't know much on the organic certifications side of things. I am sure I will have to do that in the next year or so, but I'm lucky and know all the folks who would be involved and can get some special attention!

I don't understand your light question.

54 IBC totes at 275 gallons a piece equals 14,850 gallons.

40x4x1 grow bed would be about 1,197 gallons.

That's around 17,000 gallons. I assume the IBC totes are the fish tanks? If so, your fish tank volume to grow bed volume ratio is quite off.

[kneedeepinwater]

I understand. Lucky you with all that special attention I will do some more looking around to see what I can't find out. I did do some reading on the organic cert. website and they mention if you have PT wood near or on the ground where it can leach into the soil you will not be able to become certified organic of course that's if you are growing in soil. If not mistaken I think they even stated if you have a fence made out of PT wood and some of it needs replacing you have to replace it with untreated wood. Who knows....I'll do some more checking.

With the light im asking with the ibc totes sitting about 2ft above will enough sunlight get to the lettuce beneath for them to grow correctly.

The 54 ibc totes would be cut so I was figuring 3.25x4x12in, sorry I thought I said they would be cut.

Thanks for the urbanfarmer

I have started putting the greenhouse up and I have pics I will be posting soon.

Thanks

[cedarswamp]

I understand. Lucky you with all that special attention I will do some more looking around to see what I can't find out. I did do some reading on the organic cert. website and they mention if you have PT wood near or on the ground where it can leach into the soil you will not be able to become certified organic of course that's if you are growing in soil. If not mistaken I think they even stated if you have a fence made out of PT wood and some of it needs replacing you have to replace it with untreated wood. Who knows....I'll do some more checking.

With the light im asking with the ibc totes sitting about 2ft above will enough sunlight get to the lettuce beneath for them to grow correctly.

The 54 ibc totes would be cut so I was figuring 3.25x4x12in, sorry I thought I said they would be cut.

Thanks for the urbanfarmer

I have started putting the greenhouse up and I have pics I will be posting soon.

Thanks

Filled to the rim your IBC's would be 5251 gallons plus the 1200 gallons for your 40x4 or around 6450 gallons total.

[davidstcldfl]

Hi kneedeepinwater, Looking forward to some pictures of your build...
So, what size will your fish tank(s) be ? I'm guessing it may be a few IBC's ?

Guessing your 'cut' IBC's will be media beds....? Just wondering...
- on the count of '54', will you be getting 2 media beds out of each IBC (1 from the top and 1 from the bottom) ?
- Will each bed have it's own bell siphon, or perhaps a common bell hooked to a few of them ?


Will your 40 x 4 x 1 bed be a raft/ DWC set up ? If it is....the water height will be constant, not effecting the size of a 'sump'. Folks that have 'just' a raft/DWC system, don't have to have a sump. The pump goes in the end of the last trough .

When figuring the size of your sump.....your media beds may only actually hold (as little as) 40 % of the volume in water, depending on what media you use.
Cedarswamp figured 5251 gals of water...they may only have, as little as, 2100 gals of water, because of displacement.
I'm pretty sure Oliver talked about that, in one of his AP build articles.

I wonder if the organic certifiers will aprove your IBC's....? You may need some proof that they were 'food grade/use' only...?
Also, if your 40' bed is a DWC, the liner will need to be approved also. Folks that have an organic DWC system, are using Duraskrim for the liner.
You may research Oregon Tilth. They have given organic cert, to some AP systems.

Good luck... Don't forget the pictures.

[kneedeepinwater]

Thanks for the help guys!

Well I plan on just doing one fish tank, unless plans change. Size 8lx4wx4d = 958 Gallons

Yes, the 'cut' IBC's wil be the media beds, sorry I didn't say that. I had considered using the top and the bottom for media beds but I wasn't sure how that would work because I did want to use the original drain on the bottom. I'm glad you asked that question because that was going to be one I would ask. How should I hook up the drains? I have thought about both but wasn't sure which would be the best. I read somewhere that a mega siphon is a lot of trouble?

Yes I plan on the 40x4x1 being another raft/dwc. I would like to get away with using one pump if possible so I was going to try and run pvc from the main line from the pump to feed the raft/dwc beds.

When I figured up the 4-5000 gallons for the sump I did use the 40% figure for the media beds.

I understand the water the raft/dwc system doesn't matter when it comes to the sump but I also figured in sum in case I needed to drain one of the raft/dwc beds, I figured I could drain it into the sump instead of wasting 1200 gallons of water and having to fill the system back up with 1200 gallons of fresh water.

I don't know if they would or not, it had food grade material in it from my understanding. I purchased them from piedmond bio fuels which makes bio diesel. I have a receipt for purchase.

So I need to look for Duraskrim to line the raft/dwc beds? I thought the firestone EPDM liners were ok? Are the EPDM liners ok to use in the sump and fish tank?

Thanks I will check into Oregon Tilth. It's really not a big deal if I don't get certified organic, I possible might not even try for it but I would like for things to be like they need to....just in case.

I won't forget the pics, I am going to start a new thread for those probably under commercial.

Thanks

[cedarswamp]

David's right on the volume, I assumed everything was DWC.

If I'm not mistaken some folks are having difficulty obtaining organic status for aquaponicly grown produce. I think I read that Friendly Aquaponics had lost their certification recently due to bureaucratic red tape.

[davidstcldfl]

David's right on the volume, I assumed everything was DWC.

I wasn't sure either...

If I'm not mistaken some folks are having difficulty obtaining organic status for aquaponicly grown produce. I think I read that Friendly Aquaponics had lost their certification recently due to bureaucratic red tape.

If I remember correctly, Friendly lost their 'food safety cert' due to red tape....'not' their organic cert.
Something about un-processed 'animal' waste being too close to the food product.... The inspector didn't make the connection with cold blooded VS warm blooded animals and the concern with Ecoli.