Is dried fish poo an "aquaponic" fertilizer?

[Sylvia Bernstein]

Yesterday I was at the Maximum Yield Indoor Gardening Trade show.  It is almost entirely geared at hydroponic equipment and supplies.  I came across a vendor named Clear Water Organics whose primary business is growing Rainbow Trout.  The reason why the were there is that they have come up with a product from their waste stream that they are calling simply "Aquaponics".  It is bagged fish poo from the trout farm that has been dried for two weeks (they claim this "removes the ammonia so there is no need for cycling") then they add fish emulsion.  They say that using this instead of a hydroponic fertilizer makes your system an aquaponic system vs a hydroponic system.   Hmmm...

 

Aside from an obvious definitional problem - aquaponics is a living ecosystem, not just a way of growing plants with fish poo - what other pros and cons do you guys see with this?  I like that they are recycling their waste stream, but I'm pretty skeptical that without a bacteria base to mineralize the organic material and make it available to the plants you are just going to wind up with a smelly mess.  

 

What is your opinion?

[tilly the tilapia]

hi sylvia

we did a lot of work on this aspect of using fish waste

and just adding this powder will cause no end of problems

but good luck to those that try

tilly

[Chris McMahon]

It's good for square foot gardening because you don't have any fish when doing that. I would use it when I plant carrots, onions, square foot tomatoes, etc.

[Raychel A Watkins]

Sometimes people just don't seem to get it.  I think the definition of aquaponics is the marrige or relationship of between aquaculture and hydoponics.  This as Sylvia points out is a living ecosystem.  Leave out the fish even though you use their waste it is still just hydoponics maybe you could call it organic but it is not aquaponics.  Some people have talked about going fishless .  To me this is not aquaponics either.  If people wish to do things that way it is certainly ok but they have to give it another name.  I truly think real or a perfect aquaponics system would be one where you added as little as possible.  The system should come into balance and the only thing you add is fish, fish food, plants, a little bit of organic bug killer, and some iron.  In a perfect system even the bugs would stay away.  Anybody know how to bring that about.  I think the fish poo would be wonderful for a garden of any kind.  I have 4 barrels of potatoes planted in compost.  everyday I carry fish water to them.  I don't think I can call that an aquaponic system.   But my potatoes are really growing and I am hoping for a good crop.

[Jesse Hull]

How'd you like the Max Yield show, Sylvia?

Regarding the Clear Water product, I'll agree with "Hmmm".  

Drying the effluent matter will help with the ammonia temporarily.  It would definitely not remove the products potential to create more once re-hydrated.

In the last 10 years, I've experimented with dozens of natural and OMRI listed hydroponic (hydro-organic) fertilizers, e.g., Earth Juice, Pura Vida, Bio-Bizz, etc.  All of the OMRI listers required soil or soil-less medium such as coco or peat to work well, so some might argue against it being called truly hydroponic (semantics).

From what I experienced, I'd be very surprised if the product you mentioned could simply be run through a strict non-media based hydro system in place of the synthetics that would normally be used.

My best guess is that the problems you'd encounter are the same as all of the retail ready hydro-organic fertilizers I tested:

First, the pH will shift like mad.  A measurement as low as 4, and within 48 hours or less, as high as 8 would not be uncommon.  I tried several natural pH up and down products and other buffering amendments; however, nothing maintained a healthy range for long... typically, the pH adjustment would only last a matter of hours. 

Within a week or less, despite profuse aeration, the olfactory cues would convince you to drain the reservoir with a certain quickness.  Obviously, running the resulting soup to waste on a weekly basis has it's own environmental concerns, and makes already expensive products even more costly.

Lastly, the formulas often aren't as complete as they claim.  For instance, Pura Vida lacks calcium entirely and Technoflora requires that you add their synthetically derived calcium/magnesium/iron supplement (which kinda defeats the purpose, IMO).  

After including specific types of in-line bio-filtration setups, things changed for the better.  Just as with aquaponics, however, the system has to be cycled (bacteria cultured), and there's a bit of a learning curve involved when the pH fluctuates like that. As you might guess, the pH remains fairly stable once the biology matures.  

Of course, if the formula isn't complete, nothing other than adding the missing component(s) will make a difference.

 

[Jesse Hull]

.

[Kobus Jooste]

I am actually in the second year of a project investigating the possibility of combining a modified aquaculture facility with soil based farming.  My concept is to have a system where the wastes from aquaculture, and the yields from modified aquaponics are mulched together for SOIL BASED agriculture.  I will not try to use this stuff in aquatic production because if it still contains complex nitrogen bonds, it will have to be broken down by microbial action.  My process is based on locking the wastes as far as possible into simple bonds that still require soil microbes to break it down, thus giving a "slow release" fertilizer rather than a aquaponic additive.  I do not "just dry and bag" the poo - it is just the beginning of the process I'm working on.  More on it later when we do limited promotion of our concept.

[Chris McMahon]

The Indians used to put a fish head in a hole and then plant a tomato plant on top of it. That is about as far as I will go merging aquaponics and square foot gardening.

[Harold Sukhbir]

Hi Kobus,

In the not so far future regulators may mandate aquaculture and aquaponic farms to be built next to each other. The fish farm sends the poo water to be cleaned by the vegetable farm and returned. Sounds like win/win to me. At this point there will be no more dried poo for marketing or even the soil garden. Anyone has a fish farm nearby? Go get em!

Kobus Jooste said:

I am actually in the second year of a project investigating the possibility of combining a modified aquaculture facility with soil based farming.  My concept is to have a system where the wastes from aquaculture, and the yields from modified aquaponics are mulched together for SOIL BASED agriculture.  I will not try to use this stuff in aquatic production because if it still contains complex nitrogen bonds, it will have to be broken down by microbial action.  My process is based on locking the wastes as far as possible into simple bonds that still require soil microbes to break it down, thus giving a "slow release" fertilizer rather than a aquaponic additive.  I do not "just dry and bag" the poo - it is just the beginning of the process I'm working on.  More on it later when we do limited promotion of our concept.

[Kobus Jooste]

The only issue there is that high density fish farms produce so much waste water that the ratios between waste water treatment (aquaponics side) and fish farm will not balance - you are looking at a 5 - 15% discharge from recirculating systems last time I looked (daily water percentage flush).  At present, 18 fish in my system produces 5 kg's wet mass of fertilizer material per week.  This is because modified aquaponics is used to bind the ammonia in plant tissue, preventing it getting flushed into ground water - if you do not do this, your waste water stream will still pollute the environment if it is discharged, while on the other side, in the aquaculture facility, you will need a massive exchange of water to maintain fish health.  If you look at the work in Australia on merging fish farms and aquaponics, the concentrated fish waste had to be stored and aerated - it could not simply be "used up" on a daily basis.  My work is based on a low tech low density culture on the fish side and a sustainable soil based farming practice next to it using soil rehabilitation and soil improvement farming methods. This is more in line with rural self-sustaining practice than 1st world high density intensive culture.

Harold Sukhbir said:

Hi Kobus,

In the not so far future regulators may mandate aquaculture and aquaponic farms to be built next to each other. The fish farm sends the poo water to be cleaned by the vegetable farm and returned. Sounds like win/win to me. At this point there will be no more dried poo for marketing or even the soil garden. Anyone has a fish farm nearby? Go get em!

Kobus Jooste said:

I am actually in the second year of a project investigating the possibility of combining a modified aquaculture facility with soil based farming.  My concept is to have a system where the wastes from aquaculture, and the yields from modified aquaponics are mulched together for SOIL BASED agriculture.  I will not try to use this stuff in aquatic production because if it still contains complex nitrogen bonds, it will have to be broken down by microbial action.  My process is based on locking the wastes as far as possible into simple bonds that still require soil microbes to break it down, thus giving a "slow release" fertilizer rather than a aquaponic additive.  I do not "just dry and bag" the poo - it is just the beginning of the process I'm working on.  More on it later when we do limited promotion of our concept.

[Harold Sukhbir]

Hi Kobus,

The amount of fish waste in fish farms will be high and also they won't be able to medicate fish for diseases if we want to do aquaponics with the waste water. So then it will become a question of ratios. Looks like we'll have several AP farms surrounding a central Aquaculture Farm!

[Sahib Punjabi]

:-)

Dave Donley said:

They should just call it fish manure.