Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

  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

Views: 1317

Reply to This

Replies to This Discussion

Nice, Chris! While it is certainly completely baffling to me why it wouldn't be considered organic (and, yes, I've heard the whole debate around soil...still baffling) it is certainly more sustainable that organic farming. At AeroGrow we used to toy with the simple phrase "Better than Organic". I believe that about aquaponics 100%.
Thanks Sylvia!

Peter, nice to see you here. Sounds like your crops are USDA certified organic, currently. Who is your certifyer and are they receptive to more aquaponics operations coming aboard with them? Maybe we should start a thread of US Certifying Agencies that are in favor of certifying aquaponic crop. As you know the certifying agency does not have to be in your home state. If we started a list of "friendly" agencies we would eliminate a lot of leg work for new growers.

Chris, I know there are many ex-students that still confuse some of the processes and principles, so most likely that person did tell you wrong information.

The nitrate regulation in our system is relatively simple. With a feed load of >40lbs a day, plenty of fine solids pass the clarifier and catch on the net in the filter tanks. If we clean the nets once per week they REALLY foul up. This creates large pockets of soilds that become anaerobic (no oxygen). The anaerobic bacteria convert Nitrates to N gas, reducing Nitrates as the water passes through the tanks. This condition favors fruiting plants that prefer lower N, allowing for a greater intake of Phos. If we change the management to cleaning nets 2X/week we maintain relatively high Nitrates. There are no anaerobic zones in the nets, so as water passes these tanks Nitrates are maintained. This condition favors vegetative plants like lettuce or basil.

When I clean the nets 1X/week my NO3 levels are 100-200ppm
When I clean the nets 2X/week my NO3 levels are 10-40ppm

The labor of cleaning nets can be nasty or can be simplified by a creative farmer, and you are right about the loss of those solids (nutrients) during the cleaning process. I prefer to have the ability to change nitrate levels and I see many uses of the sludge released during cleaning. Solids Removal is a very important process in Commercial Aquaponics.

Additionally, I think the term Better is so relative. Not every AP produce will be Better. I also don't like the term organic as it has so many definitions. of course there are other labels that can be used to identify our products as healthy, pesticide free, herbicide free, or just grown with fish poop!

As for the NOP certification, I think farms that are being certified have convinced the agencies that the plants are actually being grown in the media they are started in. I wouldn't think rockwool starts would qualify, but compost media or coco-coir seedling mixes could. The young plants are started in this media then set into the system. The system just waters the seedling that is going in the certified organic mix. I think that is the rationale on how they are being certified while really not being grown in the soil. The rules as they are written though do require animal wastes being used for fertilization to be composted for certain times and temps and turns. I'm not sure how an agency can certify knowing the plants are being fed on a manure that has not been composted. Any thoughts?
As to the manure thing, I think that normally applies to warm blooded manure that could carry pathogens. With Aquaponics the fish poo is not like dumping uncomposted chicken or cow manure onto crops. Is fish emulsion that is often used for organic crops "composted?"
"normally applies to warm blooded manure"...I understand warm blooded vs cold blooded and the reasoning fish don't currently transmit pathogens from fish to humans, but under the NOP standards as written does it address warm vs cold blood animal manure? I'll have to look into my regs this weekend and get back here. We are "dumping"/flowing uncomposted fish poo on or through our plant roots, so in a way it IS like dumping uncomposted chicken or cow manure onto crops. Fish emulsion is a different story all together. That product does adhere to strict standards.






TCLynx said:
As to the manure thing, I think that normally applies to warm blooded manure that could carry pathogens. With Aquaponics the fish poo is not like dumping uncomposted chicken or cow manure onto crops. Is fish emulsion that is often used for organic crops "composted?"

Charlie, I have read several publications about the UVI system, but they were braud overviews of how it works. Nothing that I have read has gone into as much detail as you have given in your posts here. Thank you for the info. Is there any publication that gets into the nuts and bolts of the operation instead of an overview? I want/need to learn more. I hope to be able to see the system one day.
I had no idea you had such control on nutrients with the nets. I too have had problems with anaerobic zones in my nets and that is the second reason I am eliminating them from my systems. I have been growing vegetative plants, fruiting plants and flowering plants side by side without playing with nutrient levels and all are growing well. I admit that I have not bothered to test for anything other than nitrates,nitrites and ammonia.

I did come up with a less messy way to clean my nets and I now sell the emulsion. The emulsion that is not sold quickly goes to my fruit trees.

As far as the organics, I am going to start a new discussion on that subject and get away from my misinformation that I posted on this thread.

Charlie Shultz said:
Thanks Sylvia!

Peter, nice to see you here. Sounds like your crops are USDA certified organic, currently. Who is your certifyer and are they receptive to more aquaponics operations coming aboard with them? Maybe we should start a thread of US Certifying Agencies that are in favor of certifying aquaponic crop. As you know the certifying agency does not have to be in your home state. If we started a list of "friendly" agencies we would eliminate a lot of leg work for new growers.

Chris, I know there are many ex-students that still confuse some of the processes and principles, so most likely that person did tell you wrong information.

The nitrate regulation in our system is relatively simple. With a feed load of >40lbs a day, plenty of fine solids pass the clarifier and catch on the net in the filter tanks. If we clean the nets once per week they REALLY foul up. This creates large pockets of soilds that become anaerobic (no oxygen). The anaerobic bacteria convert Nitrates to N gas, reducing Nitrates as the water passes through the tanks. This condition favors fruiting plants that prefer lower N, allowing for a greater intake of Phos. If we change the management to cleaning nets 2X/week we maintain relatively high Nitrates. There are no anaerobic zones in the nets, so as water passes these tanks Nitrates are maintained. This condition favors vegetative plants like lettuce or basil.

When I clean the nets 1X/week my NO3 levels are 100-200ppm
When I clean the nets 2X/week my NO3 levels are 10-40ppm

The labor of cleaning nets can be nasty or can be simplified by a creative farmer, and you are right about the loss of those solids (nutrients) during the cleaning process. I prefer to have the ability to change nitrate levels and I see many uses of the sludge released during cleaning. Solids Removal is a very important process in Commercial Aquaponics.

Additionally, I think the term Better is so relative. Not every AP produce will be Better. I also don't like the term organic as it has so many definitions. of course there are other labels that can be used to identify our products as healthy, pesticide free, herbicide free, or just grown with fish poop!

As for the NOP certification, I think farms that are being certified have convinced the agencies that the plants are actually being grown in the media they are started in. I wouldn't think rockwool starts would qualify, but compost media or coco-coir seedling mixes could. The young plants are started in this media then set into the system. The system just waters the seedling that is going in the certified organic mix. I think that is the rationale on how they are being certified while really not being grown in the soil. The rules as they are written though do require animal wastes being used for fertilization to be composted for certain times and temps and turns. I'm not sure how an agency can certify knowing the plants are being fed on a manure that has not been composted. Any thoughts?
Chris, currently there is no UVI system manual or "nuts and bolts" guide. We are hoping to put something out that we will make available for free. Besides the one-week short course, we think an intership is really what a new farmer needs. We do have students leave and later confuse processes or principles. Last year we had an ex-student come back and work with us for 3 months. She had to pay her own way, food and lodging, but she got a valuable hands-on experience. I may can put something like that together for you if you want to come spend some time down here. pm me about this if you are interested.

As for the gook in the nets, I don't think you should sell it as "Emulsion". Emulsion is derived from fish guts that's a byproduct from the fish oil and fish meal industries. Most fish emulsion sold on the retail market is concentrated and has about a 5-3-3 NPK ratio. The solids/sludge derived from cleaning nets is not the same as emulsion. It's not nearly as strong as emulsion. If you are selling it, you may want to eliminate the use of Emulsion as a descriptor.

Peter, thanks for the info...maybe there are not quite soil microbe snobs...perhaps water microbe dummys!

Does friendly's system have any issues with potassium or iron deficiencies?

Thanks.

Chris are you leaning towards a gravel bed vs the nets in a tank for solids removal. What do you think of a tiered gravel bed or media removal. Something in the order of fish tank to 3/4 gravel bed cascading to 3/8 gravel and back to rafts. Heavily stocked with worms and plants in gravel bed. match gravel beds to fish tank volumn. I am going to build my next raft system along those lines. No clarifier or degassing tanks. Interested in you thoughts.

Very Very Very interesting convo
I have long pondered the differences

i have one last concern, i please i do want to compare any systems.

However

In the case of solid removal i have a concern in the differences,

UVI uses a combination of a "baffle" and net filter

While i saw Mr. Murray using swirl and particulate filter- made of "spaghetti" material

now to the meat of the matter there has been a publication by Dr. Rakocy and the team from the UVI on the difference in operation of a swirl and net filter(which i have uploaded)

However is there any study in the difference between net and particulate filter and the effects on the system when cleaning is done so on
  

Very Very Very interesting convo
I have long pondered the differences

i have one last concern, i please i do want to compare any systems.

However

In the case of solid removal i have a concern in the differences,

UVI uses a combination of a "baffle" and net filter

While i saw Mr. Murray using swirl and particulate filter- made of "spaghetti" material

now to the meat of the matter there has been a publication by Dr. Rakocy and the team from the UVI on the difference in operation of a swirl and net filter(which i have uploaded)

However is there any study in the difference between net and particulate filter and the effects on the system when cleaning is done so on 

there wont be any detail informations about UVI system, as it is Dr. Rakocys IP. Im not sure if he still offers his course at UVI (as he retired), but if he does then you will get the detail knowledge there. For Friendlys you pay 99 Bucks and you get all the informations you need. When it comes to commercial systems, knowledge is not for free - very understandable. In my oppinion is Friendlys system a modification of the UVI system, and if im not completely wrong then the Friendly owner visited a course of Dr.Rakocy at UVI :D

the FAP farm relies heavily on the use of gammarus and other detritivores to help keep their system clean. in their largest system they have a series of 3 solid settling tanks with the last one is filled with fish netting, then these dump into a degas / bubbler tank to be dispersed into 3 sets of 4 troughs...

now it was seen that in the beginning the fish waste would accumulate in the net tanks, and the netting would need to be removed and cleaned... a very dirty job. the one day a small creature was noticed in the water. not knowing exactly what it was it was left to it's own devices, but the system was put under tighter surveillance and the creatures were being researched. over time the amount of fish waste began to drop in the net tanks, and the number of these creatures began to grow.

as it turne dout the creatures were gammarus, a detritivore. (poo eating water crustacean) these little guys were actually eating the poo and mineralizing it. my guess is a bird that was swimming in a near by stream happened to drop a few of these guys into the systems... but that's not a bad thing. these guys are natural filters. this would explain why the FAP farm doesnt have complicated filtering systems.

my guess to the lack of pH swings that the FAP farm didn't have to deal with is once the systems micro biology gained a foot hold, it gave the system a bit of autonomy... meaning the things living in the system were striving for their own survival, just as they would in any new ditch of pond.... what FAP did was essentially create a lake and stream on a small scale.... fish tank would be the lake, and the grow beds the stream... 

also the FAP's lowered fish density and yet proper plant growth could be attributed to the large amount of mosquito fish freely swimming about the troughs eating for free on mother natures bill...  these guys would eat the mosquito eggs and larva and inturn relieve themselves directly into the troughs. this could be a bad thing... if the gammarus hadn't already made themselves at home in the troughs and handled the mosquito solid wastes as well as anything that would have found it's way into the system and died...

(=

Reply to Discussion

RSS

© 2019   Created by Sylvia Bernstein.   Powered by

Badges  |  Report an Issue  |  Terms of Service