System design

[Sylvia Bernstein]

What are your thoughts on system design?  Media vs raft.  Deep media beds vs shallow.  Siphons vs timers.  Tell us your thoughts and let's get the conversation rolling

[Alan]

I've been following these boards with great interest. So firstly a big thanks you all for sharing so much info.
I've got a small barrel ponics system (Travis Hughey) working well but....I want to go commercial.
Before this interest in aquaponics I had a large hydroponic set up using NFT. Now in storage. So here I am with almost 2000 linear meters of NFT pipes, fittings etc and no source of information on how to convert toa continuous flow aquaponics system. Seems such a waste if I do not use all this stuff.
So questions,
1 Why so little info on NFT conversion? Any scientific reason(s)?
2 There seems to be loads on info on tank size to grow bed ratios etc. Is there some way to computer flow rates and nft runs per 1000 litre tanks etc.
Additonal info. I'm based in Thailand with had a warn climate all year round.
Plan on raising Tilapia and growing salads. I am thinking say 4 no 1000 litre tanks all connected (so I can harvest fish every 5 weeks or so). Set up a continuous 'flow' system.
Help me out here please.

[Jeff Givan]

Alan,
This is such a new way to go, I say blaze a trail! Get those NFT's out of storage, dust them off and go with your plan. Adjust as you see fit! Never know till you go for it. Try not to kill the fish, and if you lose a plant or two along the way so what! What works for one may not work for another, so what your planning might work really well for you! Keep us posted!

Alan said:

I've been following these boards with great interest. So firstly a big thanks you all for sharing so much info.
I've got a small barrel ponics system (Travis Hughey) working well but....I want to go commercial.
Before this interest in aquaponics I had a large hydroponic set up using NFT. Now in storage. So here I am with almost 2000 linear meters of NFT pipes, fittings etc and no source of information on how to convert toa continuous flow aquaponics system. Seems such a waste if I do not use all this stuff.
So questions,
1 Why so little info on NFT conversion? Any scientific reason(s)?
2 There seems to be loads on info on tank size to grow bed ratios etc. Is there some way to computer flow rates and nft runs per 1000 litre tanks etc.
Additonal info. I'm based in Thailand with had a warn climate all year round.
Plan on raising Tilapia and growing salads. I am thinking say 4 no 1000 litre tanks all connected (so I can harvest fish every 5 weeks or so). Set up a continuous 'flow' system.
Help me out here please.

[Alan]

Many thanks. I just needed a kick start!!!!


Jeff Givan said:

Alan,
This is such a new way to go, I say blaze a trail! Get those NFT's out of storage, dust them off and go with your plan. Adjust as you see fit! Never know till you go for it. Try not to kill the fish, and if you lose a plant or two along the way so what! What works for one may not work for another, so what your planning might work really well for you! Keep us posted!

Alan said:

I've been following these boards with great interest. So firstly a big thanks you all for sharing so much info.
I've got a small barrel ponics system (Travis Hughey) working well but....I want to go commercial.
Before this interest in aquaponics I had a large hydroponic set up using NFT. Now in storage. So here I am with almost 2000 linear meters of NFT pipes, fittings etc and no source of information on how to convert toa continuous flow aquaponics system. Seems such a waste if I do not use all this stuff.
So questions,
1 Why so little info on NFT conversion? Any scientific reason(s)?
2 There seems to be loads on info on tank size to grow bed ratios etc. Is there some way to computer flow rates and nft runs per 1000 litre tanks etc.
Additonal info. I'm based in Thailand with had a warn climate all year round.
Plan on raising Tilapia and growing salads. I am thinking say 4 no 1000 litre tanks all connected (so I can harvest fish every 5 weeks or so). Set up a continuous 'flow' system.
Help me out here please.

[Jeffrey Walls]

I am running NFT on a 650-gallon tank w/trout. I have a total of 60 feet of tubing with 120 grow sites. I have switched between growing on a timer and continuous flow. No real preference but I have noticed that continuous flow in the winter keeps the tubes from freezing and keeps the root temps close to 50F except on the coldest of nights. I do run supplemental heat for those nights.

The biggest problem I ran into originally was that I need to get more of the solids out before sending to the grow tubes. I put in a settling tanks and that has diminished cleaning time of the tubes dramatically.

As far as conversion numbers...... beats me. I do know this, I could use more grow space, so I am building more tubes for the upcoming season. Using 3-inch tubes (others are 6") for baby spinach as I have a restaurant that said they would buy all I could grow. (hey, this may pay off after all! Other than the yummies I have grown for family use:-))

I am also running two 40-gal totes with vermiculite that run on continuous flow (very slow flow). Good for root crops.

Sorry I couldn't give any specifics as far as numbers go but just wanted you to kniow that there are NFT systems out there.


Your system is going to be quite large it seems!

[TCLynx]

Why no numbers for NFT, well perhaps it's cause not so many people have done it on a scale where they could really research and produce numbers. Most of the numbers and research come about when a university gets involved and does it.

But I expect you can do some extrapolating from raft culture to figure out how much plants you need to support a particular fish load. I'm not sure if the info from raft culture for bio-filter will carry over though so you probably will need some additional bio filter in addition to the solids removal.

One note about NFT which you probably already know from Hydroponics is that temperature of the water can heat up and loose oxygen on it's way down runs of tubes that are too long.

Anyway good luck with it.

[Emma Lysyk]

What's NFT?

[Jeffrey Walls]

Nutrient Film Technique. The roots are exposed to nutrients via a thin layer of liquid passed along the bottom of a pipe or gutter type grow tube.

Emma Lysyk said:

What's NFT?

[Jeffrey Walls]

I have a distribution tube that sprays each grow site inside the grow tube so it actually aerates the water. In the winter I welcome the warming that comes when the sun shines! Plus my tubes aren't THAT long so it doesn't really come into play.

[TCLynx]

Spray heads at each plant site????? How much issue do you have with the spray holes or heads plugging up with bio-slime and solids?

Jeffrey Walls said:

I have a distribution tube that sprays each grow site inside the grow tube so it actually aerates the water. In the winter I welcome the warming that comes when the sun shines! Plus my tubes aren't THAT long so it doesn't really come into play.

[Emma Lysyk]

Oh! Thanks. I probably should have guessed that... Forgive me, I haven't had my morning coffee, yet.

Jeffrey Walls said:

Nutrient Film Technique. The roots are exposed to nutrients via a thin layer of liquid passed along the bottom of a pipe or gutter type grow tube.

[Emma Lysyk]

So would that make it a top drip system?

Jeffrey Walls said:

I have a distribution tube that sprays each grow site inside the grow tube so it actually aerates the water. In the winter I welcome the warming that comes when the sun shines! Plus my tubes aren't THAT long so it doesn't really come into play.

[Emma Lysyk]

Here is the photo of the bubble tubes that pose a problem: http://aquaponicgardening.ning.com/photo/small-problem-and-temporar...

They go into these two tubes that feed into the under gravel filter: http://aquaponicgardening.ning.com/photo/fountain-pump?context=albu...

I really don't want to dig everything up just to move those tubes, and don't know how much damage would be caused if I just hacked off those unruly ends.

Currently, I wrapped two stacks of 2x4s in saran wrap and set the grow bed atop it, and put a window screen across that side of the tank so the fish wouldn't jump out.

Does anyone have any more-permanent solutions they can think of?