Aquaponic Gardening

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  I have been reading on some discussions where people are comparing UVI and Friendlies systems. There have been comparisons on fish stocking densities which are very misleading mainly because these are COMPLETELY different systems. They do have similarities such as they use tilapia for the fish, they use the raft method and have solids settling. Beyond that there is not much else in common.
   UVI is in a much warmer climate which keeps the ambient water temperature warmer and favors fish production over crop production. Higher water temps means more air has to be pumped into the water to keep the DO up. The fish grow much faster because their matabolism is working faster and they have to be fed more.
  The biggest difference between the two is that UVI is a chemical based system that relies on calcium hydroxide and potassium hydroxide to balance their pH. Hydroxides are highly caustic chemicals.The hydroxides are used as a reactant, the more that is added the higher the pH. When UVI raises pH with caustic chemicals they are also killing bacteria and their nitrates swing. As the bacteria gets re-established, they naturally drop the pH until the point where more chemical is added causing another nitrate swing. They partially crash their system to balance the pH. Hydroxides are not organically certifiable.
  Friendly has replaced the hydroxides with calcium carbonate(sea shells). They have eliminated potassium carbonate as it is not certifiable. Carbinate acts as a buffer. When the pH drops below neutral is dissolves the carbonate and slowly brings the pH back to neutral. When the pH is back to neutral it stops working and waits for a lower pH before it starts working again. There are no drastic pH or nitrate swings in this buffered system. Friendly's systems are certified organic and there is no way the UVI system could do that with their current operation.
  This use of a pH buffer has made a much more natural system where more species are able to thrive and add to the ecosystem. I doubt that worms, gammarus and midge fly larvae would be able to live in a chemical based system. In my systems I rely on these other species to help convert fish waste to nutrients and keep the environment clean.
 
  I just wanted people to realize that a comparison of the two systems is not as simple as looking at fish densities. They are two different systems that share some similarities.

I

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Thanks for the post, Chris. Good explanation. When first researching aquaponics, I came across the UVI system on the first try and right then and there decided that if it was going to be that complex and costly, then AP was not for me. I would just stick with hydroponics. I also came across BarrelPonics, which still seemed very complex at that time. After studying that system for while, it seemed simpler. Fortunately I decided to continue researching and came across Friendly. I decided to invest $99.00 in the Micro System manual and I was not disappointed provided that what they were saying was true. After a little more research it seemd that Friendly had a viable system. I wasn't sure and still am not sure if that system will work in the New Orleans Area. I would need a greenhouse during parts of winter and our summers have days of sustained 90+ temperatures, with nights around the 80's. Unfortunately, my situation is such that I am not able to build a system at this time and do some testing. Reading and studying the Friendly system, I determined that there are certain plants that do not seem to do well in that system. I'm not much of a gardener, but have been around long enough to know that there are plants that like drier feet than what a DWC system would offer and I imagine that that is the reason that some plants do no do well in that system. Hopefully the future changes that soon.

One of the benefits of this Community, and a great, big thankful hug to Sylvia for starting it, is that we get to experiment vicariously through other aquapons without the need to be total pioneers unless we want to. I personally look upon AP the same way I look at a computer program. Just let me load it into the computer let me get working. I don't want to be a programmer. This community will allow me to do that should I so choose. And while we are on the subject of appreciation, I really do appreciate all those folks who share and contribute their hard-earned information and experiences.
The whole solids removal part of the UVI system also makes for far higher fish stocking density than in the Friendlies Micro systems or media based systems that retain the solids.

pH is plenty easy to keep buffered using shell grit or lime stone, I don't know why anyone would want to use the more caustic substances. I do find that nitrates do tend to be higher with a higher pH it seems but that is only me observing a hand full of systems.
Nice sentiments, Gus. Hugs back at you :D

And thanks for posting this, Chris. I admit that I'm a neophite when it comes to the deep differences between these two systems, other than stocking density, but I've interviewed Dr. Rakocy for several hours for BYAP magazine and been through Nelson and Pade's training on his systems. I'd like to question where you are getting " UVI is a chemical based system that relies on calcium hydroxide and potassium hydroxide". I don't remember seeing that reference in my dealings with any of them, but this doesn't quite sense to me. Kobus posted this summary of their system the other day that I'll repost here (I admit, I still haven't read it :P ). Here you go....
Attachments:

Page 3 of the document that you posted explains the base additions. I have talked with an attendee of the UVI course who saw drastic swings in pH and nitrates first hand.
Sylvia Bernstein said:
Nice sentiments, Gus. Hugs back at you

And thanks for posting this, Chris. I admit that I'm a neophite when it comes to the deep differences between these two systems, other than stocking density, but I've interviewed Dr. Rakocy for several hours for BYAP magazine and been through Nelson and Pade's training on his systems. I'd like to question where you are getting " UVI is a chemical based system that relies on calcium hydroxide and potassium hydroxide". I don't remember seeing that reference in my dealings with any of them, but this doesn't quite sense to me. Kobus posted this summary of their system the other day that I'll repost here (I admit, I still haven't read it ). Here you go....
Thanks for explaining this so well, Peter. Does Dr. Rakocy advocate adding those chemicals daily? While I might not describe it as a "chemical based" system, it sure seems to be far further from organic by any standard than the Friendly system. Is that fair?
So busy here and I just lost a long reply before hitting send!! So, let me shorten things a bit in response to Chris's post above.

I cannot comment much on Friendly as I've never seen his system in person. I can comment on the UVI system though as I have had the pleasure of working with Dr. Rakocy for the past 12 years here in St. Croix. As Chris mentioned these are 2 completely different systems. I'm not really sure why this thread came about. We are comparing apples and oranges, so there are obviously many differences.

One UVI system produces about 11,000 pounds of fish/yr, but I wouldn't say our system favors fish over crop production. With the right marketing and crop selection the crops can bring in 3/4 of the revenue for the system.

There are many inaccuracies in your paragraph about chemical additions. How do come to the statements you made above? Calcium Hydroxide is NOT highly caustic. Our additions of Ca(OH)2 and KOH do NOT kill bacteria and do NOT cause nitrates to swing. Re-establishment of bacteria does NOT lower pH. We do NOT partially crash our system when balancing our pH levels.

I think Kobus hits the nail on the head in this discussion. LD vs HD systems require different management methods. Chris, pH drops in our system primarily due to the process of nitrification. I'm sure you know that is where the beneficial bacteria convert ammonia to nitrite to nitrate. Our system is fed about 40lbs a day and there is a lot of nitrification going on continuously. H+ is released during this process, in turn pH drops. That's it. There is no killing of bacteria and re-establishment. As pH drops below 7.0 to 6.9 I add a small amount of Ca(OH)2 to adjust the pH up to 7.0-7.1. A couple days later as the pH naturally drops to 6.9 I use a small amount of KOH to adjust back to 7.0. From there I alter Ca or K additions. KOH is very caustic and handlers should be cautious and careful when applying, but our research indicates Potassium is a required supplement under our growing conditions. Also, we use a base addition tank in our system where I can add the stock hydroxide. Throughout the day there is a small stream of water that enters and exits this tank, allowing for a small quantity of base to enter the water over a long period of time. The base additions do not kill bacteria, fish or plants. I find the Calcium Hydroxide and Potassium more soluble and consistant than using sea shells. Our system has over 100m3 of water. I imagine there would be a large requirement of shells to do that job (also a zone to keep the shells). Here in St. Croix we are NOT allowed to collect shells from the beach, so the cost of importing shells would have to be considered. Hawaii is fortunate, but many AP setups would also have to import their shells. I would also be careful adding the shells as they may harbor fish parasites.

In no way are we trying to develop a "certified organic" system. The current rules as written do not allow the certification of aquaponic crops. Oregon Tilth has approved Friendly crops, but I think they may be skirting the rules and I don't expect AP systems to be certified for much longer. That's just my opinion though.

As Peter mentioned we are able to regulate Nitrates by changing the cleaning frequency of our filter nets (not killing bacteria). I think the UVI system is unique in that we can change the levels of Nitrates to favor different types of plants. We are not seeing Nitrate swings, rather regulating levels to where we want them either for vegetative or fruiting plants. Peter I think you are right about the future of NOP rules concerning aquaponics, but if you want to see if you can certify for now I would contact Oregon Tilth as a certifying agency.

Sylvia, we add these chemicals as needed to adjust pH. Usually 2-3x/week. Also we have to add Chelated Iron. I use Iron DPTA and try to maintain 2mg/L. If Iron falls below 2mg/L plants will start to show signs of yellowing. I cannot produce crops continuously in our UVI system without Iron additions.

Hope this "clarifies" some issues address in the original thread.

Charlie

- I am attempting to upload a photo of our base addition tank setup. look for the photo attached here
Attachments:
Fantastic information, Charlie! Thank you so much for chiming in on this conversation and clarifying some critical points about the UVI system. Very interesting, indeed.
Hello Peter,

Having read the NOSB crop production recommendations per the link you shared (thank you),
while "Aquaponic" is not specifically mentioned as a means of growing, what "Certification" if any do you think will apply to Aquaponic produced produce..."Naturally Grown"?

Whatever it is, I would rather buy that any day over "Organic" certification any day of the week.



Peter Shaw said:
Hi Charlie,

glad to see you are still there, and busy, that's great, and I saw you are doing a workshop on the mainland.

My certifier (CCOF) has one aquaponic system certified and they are willing to work with me, but I do not see much future in that so I am not really concerned. Oregon Tilth was not very responsive to phone calls or getting back to me.

We are using Koi for now since technically Tilapia are not legal in our part of CA. Besides the processing of fish for sale is a huge issue that we are not interested in. Koi, while not completing the cool fish and produce cycle will have a greater return per pound of fish.

Here is the link to the NOSB crop production recommendations

http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELPRDC5083203&am...

cheers

peter

Aloha Charlie, I have obviously been misinformed about the UVI system by individuals who have been there and did not fully understand the process. Some of my statements were based on this misinformation. My intention of the post was to make people aware that comparisons of the two systems is "like comparing apples to oranges". Thank you for the clarification!
Charlie Shultz said:
So busy here and I just lost a long reply before hitting send!! So, let me shorten things a bit in response to Chris's post above.

I cannot comment much on Friendly as I've never seen his system in person. I can comment on the UVI system though as I have had the pleasure of working with Dr. Rakocy for the past 12 years here in St. Croix. As Chris mentioned these are 2 completely different systems. I'm not really sure why this thread came about. We are comparing apples and oranges, so there are obviously many differences.

One UVI system produces about 11,000 pounds of fish/yr, but I wouldn't say our system favors fish over crop production. With the right marketing and crop selection the crops can bring in 3/4 of the revenue for the system.

There are many inaccuracies in your paragraph about chemical additions. How do come to the statements you made above? Calcium Hydroxide is NOT highly caustic. Our additions of Ca(OH)2 and KOH do NOT kill bacteria and do NOT cause nitrates to swing. Re-establishment of bacteria does NOT lower pH. We do NOT partially crash our system when balancing our pH levels.

I think Kobus hits the nail on the head in this discussion. LD vs HD systems require different management methods. Chris, pH drops in our system primarily due to the process of nitrification. I'm sure you know that is where the beneficial bacteria convert ammonia to nitrite to nitrate. Our system is fed about 40lbs a day and there is a lot of nitrification going on continuously. H+ is released during this process, in turn pH drops. That's it. There is no killing of bacteria and re-establishment. As pH drops below 7.0 to 6.9 I add a small amount of Ca(OH)2 to adjust the pH up to 7.0-7.1. A couple days later as the pH naturally drops to 6.9 I use a small amount of KOH to adjust back to 7.0. From there I alter Ca or K additions. KOH is very caustic and handlers should be cautious and careful when applying, but our research indicates Potassium is a required supplement under our growing conditions. Also, we use a base addition tank in our system where I can add the stock hydroxide. Throughout the day there is a small stream of water that enters and exits this tank, allowing for a small quantity of base to enter the water over a long period of time. The base additions do not kill bacteria, fish or plants. I find the Calcium Hydroxide and Potassium more soluble and consistant than using sea shells. Our system has over 100m3 of water. I imagine there would be a large requirement of shells to do that job (also a zone to keep the shells). Here in St. Croix we are NOT allowed to collect shells from the beach, so the cost of importing shells would have to be considered. Hawaii is fortunate, but many AP setups would also have to import their shells. I would also be careful adding the shells as they may harbor fish parasites.

In no way are we trying to develop a "certified organic" system. The current rules as written do not allow the certification of aquaponic crops. Oregon Tilth has approved Friendly crops, but I think they may be skirting the rules and I don't expect AP systems to be certified for much longer. That's just my opinion though.

As Peter mentioned we are able to regulate Nitrates by changing the cleaning frequency of our filter nets (not killing bacteria). I think the UVI system is unique in that we can change the levels of Nitrates to favor different types of plants. We are not seeing Nitrate swings, rather regulating levels to where we want them either for vegetative or fruiting plants. Peter I think you are right about the future of NOP rules concerning aquaponics, but if you want to see if you can certify for now I would contact Oregon Tilth as a certifying agency.

Sylvia, we add these chemicals as needed to adjust pH. Usually 2-3x/week. Also we have to add Chelated Iron. I use Iron DPTA and try to maintain 2mg/L. If Iron falls below 2mg/L plants will start to show signs of yellowing. I cannot produce crops continuously in our UVI system without Iron additions.

Hope this "clarifies" some issues address in the original thread.

Charlie

- I am attempting to upload a photo of our base addition tank setup. look for the photo attached here
I have been operating two raft systems that have net tanks. The oldest system has been running for a year now. During this time I have cleaned my nets numerous times. I have had only 2 instances where my nitrates fluctuated. Both times solids were released from the nets and got into the troughs due to errors on my part by not isolating the flow. The nitrates spiked up for a time and then returned to normal. Subsequently the roots of the plants nearest the inflow got mucked up with solids.

The second time I had to clean nets and was elbow deep in fish s**t, I decided there must be a better way!! I began researching other methods of solids removal. My system are evolving to reduce the nasty labor of net cleaning and keeping the nutrient in the systems.
Well said Kobus :-)


Kobus Jooste said:
I think you are approaching something very important. Aquaponics is sustainable, produces a fantastic crop, but cannot be labelled organic in many countries (soon yours?) due to the "not in soil" condition (does gravel count?). I have been under the impression for some time that a concerted effort from all commercial aquapons internationally will be needed to create a brand awareness and niche for aquaponic crops. Sustainable, high grade produce such as ours should find a good marketing strategy!

Peter Shaw said:
Hello Sahib,

I do not know what this will be called, there was a large discussion on the backyard aquaponics site a few years ago, as the Australians and New Zealanders have been up against this limitation for longer than us in the states.

perhaps when aquaponics becomes a bit more main stream we will be able to call it what it is.

cheers

I am actively teaching people that aquaponic produce is better than organic. I hope that through education of the public, aquaponics will be held to a much higher standard.

Kobus Jooste said:
I think you are approaching something very important. Aquaponics is sustainable, produces a fantastic crop, but cannot be labelled organic in many countries (soon yours?) due to the "not in soil" condition (does gravel count?). I have been under the impression for some time that a concerted effort from all commercial aquapons internationally will be needed to create a brand awareness and niche for aquaponic crops. Sustainable, high grade produce such as ours should find a good marketing strategy!

Peter Shaw said:
Hello Sahib,

I do not know what this will be called, there was a large discussion on the backyard aquaponics site a few years ago, as the Australians and New Zealanders have been up against this limitation for longer than us in the states.

perhaps when aquaponics becomes a bit more main stream we will be able to call it what it is.

cheers

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