Backyard Aquaponics
A place to discuss aquaponics

If you're not using sumps and siphons are you relying entirely on gravity? How are you getting the water back up to the FT? Could you expound on why you do not like these two?

I don't like siphons as they they become more unreliable as they approach optimal efficiency. The additional plumbing is a substantial added construction cost.

I know people will shake their head at my inconsistency when I have said I will use IBCs exclusively but I think their mobility and modularity outweigh the extra expense in the application.

I don't like sumps because they are inherently a compromise, they add expense to construction costs, they are immobile and take up space.

There are a few reasons for not offering a description of my system design ideas.

There is no working prototype yet to demonstrate that they even work so I'll wait till I've trialled it myself and then decide if I would show it to others.

I don't want to throw away what may be a competitive advantage to myself and future partners.

I'm a sensitive flower afraid of the spotlight and having to defend my ideas.
Actually the last is BS but I wanted to make you smile before I tell you no.

Theres a very common theme Ive seen amoung commercial operations over the years and in a way they seem fall into one of two catagories. Both are directly related to scale. And this is just my observations.

Small scale, probably better described as hobby farms. It seems to me that if the scale isnt there then these buisnesses use a multitude of other methods to suppliment income, usually training, courses and books then followed by products that they produce themselves like creams, dairy, jams, pickled products, eggs, honey, etc etc. These smaller scale buisnesses are usually selling at markets, local resturants and alike. I would assume normally these buisnesses wouldnt be supported by gov grants.

Large scale, mass ton production of both fish and plants. Sole buisness is to pump out both products, usually one type of fish and only a few different types of fast growing plants like lettuce, basil etc. All automated, DWC, clever filtration and nutrient controls, climate controled, lighting, large amounts of employees. Selling to major food chains. Supported by gov grants.

I don't think you're going to find anyone who thinks of 250g fish tanks as commercial. Sorry, the numbers just aren't in it. IBC's scream "Backyard Aquaponics" - not "Commercially Viable"

I have stated as clearly as I can that AP is neither commercial aquaculture or commercial hydroponics and yet the refrain continues that such a tank wouldn't be viable in aquaculture but this isn't aquaculture it's aquaponics. If i was doing pure aquaculture, I wouldn't use IBCs either.

I hear similar arguments for DWC because they use DWC and NFT so we must use them to be commercially viable, but this isn't hydroponics.
In hydroponics they don't have fish waste in their water so they don't have to add extra processes to filter their water so the roots of their plants get chocked up with crap and die.

In AP the gravel beds do the work of the aquaculture filter and the hydroponics DWC vessel and yet everyone continues to try to graft these on where they don't go well. Everyone wants to run commercial aquaculture stocking levels in AP and it just doesn't work. In reaching for the ring they crash the merry-go-round.

The sooner folk realize AP is it's own creation the sooner fish will stop dieing prematurely and people will design plant that suits AP not something else.

When I read ack over my comments, I realize how bombastic they read. I am not like that in person it is just that the I like AP and not AQ or AC.

I dont think anyone has said that they would be no good for AQ, I think whats being said is they are no good for large scale anything.


Nope. The large scale AP commercial systems use DWC and NFT. As I (and Stuart) mentioned earlier, there are reasons for this.



Im not sure what you mean by this statement. AP has been around around a long time.

Hey Charlie,

The rag on IBCs above is a classic example of what I' banging on about. To my mind it just doesn't ring in sympathy with the facts of AP.

Let see.

If we take the 2:1 ratio of water to wet gravel everybody thinks that means I could have a 2000 liters of wet gravel and that is correct and safe and that's great. It is the configuration of that 2000 liters that is telling as hardly anyone goes for the largest area that they can make with that 2000 liters. That's enough wet gravel for a bed 6 square meters at 300mm deep and if you make them 250mm deep you get 8 square meters...Driven by one IBC. When you get to 12 IBCs you can drive 100 square meters of grow beds at that depth. You get the picture.

Now I get someone telling me they would consider anything below 15 cubic meters as un-viable.....What? Where are are you going to put the 150 square meters of growbed for that puppy? This doesn't even take the complexity and cost of the plumbing circulating that water into consideration. And I want twelve of them to raise several cohorts of several species at different stages of production. Unviable?

Show me someone who is maximizing the growbeds attached to their IBC first, then let them add more fish tank. The OP that speaks most frequently about this is TCL because I think she really gets it. Why does she get it? Because for her it's a business and I pretty sure Ryan gets it as well.

Any clever operator in a commercial venture will maximize the growbeds for each tank or they are throwing away money. If I ever do this commercially you had better believe I will be trying to run beds 100mm deep for plants such as lettuce, Pak choi,etc: That will be 20 square meters from 1 IBC. If I had to supplement with CC occasionally...so be it. Got to keep those beds making money.

If I want to grow plants and fish I can do it in my back yard but you don't go into business to grow fish and veg or employ the local population or because it's good for the planet....YOU are in business to make MONEY.

I think I get what you are saying about maximizing growing area with GBs but I would offer two counter thoughts.

The first is that the developers of the 2:1 ratio were the Seperano's and they relied on their gravel beds as their sole plant growing component. After all their trials they settled on the 30cm deep GBs because that is what worked for them. Some time ago there was a quite violent agrument about the depth of GBs and what was "best". Other than the Seperano's and another American of the same vintage I don't know any one who has expirimented with different depths of gravel side by side. Lots of people have tried different depths and have shown that shallower and deeper beds work just fine but that is all we can really say.

Two: My approach is the opposite of yours. I want to minimise the footprint of the GBs to make more room for what in my opinion are the more commercially viable production methods of NFT and DWC. In a hybrid system I would possible grow fruiting crops like toms and caps in GBs but all of the high turn over crops like salad greens and herbs would be in DWC or MGNFT.

You say you don't like the extra labour of varying the densities of the plants in DWC or NFT but in MGNFT systems this process is 100% automated and in DWC it can be. Even if it isn't though the labour of transplanting in rafts is pretty minimal and is significantly less than the extra capital and energy costs of not doing so.

Also in AQ the labour required to manage a system is based upon the number of tanks. Some systems are getting production numbers of less than one full time employee per 100t of production without automated feeding systems. With automated feeding systems they are still trying to work out where the ceiling is but it seems to be more of a risk management concern rather than a technical issue.

With many IBCs as FTs the labour to look after all those tanks will be huge. Factor in moving them in and out with the changes of season will make the job even bigger. If you can successfully monitor the health of all those individual cohorts will give you the ability to finely control their growth but the key word there is if.

You obviously have your own ideas but I'm confused as to why you are so adverse to what you describe as labour intensive plant growing methods but condone labour intensive fish husbandry

I'm of two minds.

My media beds are still out performing my DWC, I'm sure it's because my fish aren't big enough yet, so not enough waste produced. But the media beds are still going far better. Seeding is far easier, just sprinkle away (but difficult when you compare with a commercial seeder).

The two major problems I see with the media beds in a commercial setting, if you need to clean out the GB's because you've had too much fish waste going through it. It's a major undertaking, and could easily break pond liner during the cleaning.

The second would be pump size. Correct me if I'm wrong, but doesn't media beds require a larger flow of water to kick off, and any sizable farm will need a far larger pump than DWC would need, so more electricity cost. Although, this might be lower if you don't need as much of an air blower.

You could possibly design a GB as a gravel filter that was capable of being back washed but it would be tricky to make it a grow bed and back wash capable filter and I'm not sure you would want to. Really if you a minimising your GB volume so that the possibility of cleaning your GBs is possible let alone likely I'd say you would be better off going for a separate solids removal/processing system like a mineralisation tank. The engineering and risks in running a GB that could clog would make me rather nervous.


Nope. You size the flow to the nutrient load which is based on how much you are feeding the fish.

Stuart,

I've nothing against any of the recognized HP systems in HP, in fact, if I did purely HP I'd use them myself. I agree very efficient use of space. Plant costs are higher than I would like but that is true in nearly everything I purchase, I'm a tightwad.

2:1 is just the beginning I'd certainly be experimenting to find the limits of this particular envelope. I suspect this ratio can be pushed with system maturity but may require supplements along the way.

It's not just the labor the negatives keep stacking up. Every penny saved in plant and operating cost goes straight to the bottom line shortens ROIs and drives foward profitability, it's smart business.

It's still early but, my plant species choices will likely not be short duration high tunover low margin. Perhaps after more lucrative markets.

Driving fish tanks hard is a dangerous strategy, it's much safer to design fish safety into the setup as a whole. I would be satisfied and take what safe fish production I can get without overly stressing them. In a very real sense fish production is almost a byproduct of growbed circulation. The commercial size and nature of the associated fish production is as a byproduct of hopefully voluminous plant production.

NFT an DWC do not slip effortlessly into my particular designs' idiosyncrasies particularly during the early stages of the business' logical roll out sequence. Perhaps as an adjunct to the dedicated environmentally controlled fish grow out systems when/if they are installed.

colum,

There are no large pumps in my system design.

But growing commercial food fish in IBC's just isn't that smart to begin with. All that work for a small amount of fish (even if you have several IBCs) seems very inefficient unless you are getting a very high premium on your fish sales in the area.

Sam,

I know what you mean but I don't think I could get a smaller tank any cheaper than an IBC.

We do have a commercial vegetable bin that's about 750 liters it's called a mega bin but they are multiples of the price of an IBC. Just kidding.

If I was doin Aquaculture I'd go for bigger tanks....honestly I would, but this is Aquaponics.

Just one IBC running reasonably conservative stocking levels is enough tank to grow out somewhere between eighty and one hundred plate size per year maybe less for safety so 40 kgs annually. Now take that figure and multiply it by 100 a pretty conservative 4000 kgs annually as a byproduct of pumping water around my growbeds. This is the fish production of just two of my 8 by 100 meter greenhouses. Add to this the green production of eight hundred square meters of growbeds. That's just two greenhouses.

I would be planning on adding two additional green houses every six months so when I reach ten I'm producing 40000kgs of fish as well as the green product of 4000 square meters of growbeds annually.

At that level of expansion, ten greenhouses, we are only covering approximately one hectare if it's a four hectare site you could triple these numbers again before you reach the sites greenhouse capacity. Is there going to be money in it? I don't know you'd have to give it a go, if it works expand, if not... shut it down.

At the end of the day, doing AP like that is more like market gardening than fish farming the fish just fertilize the plants and provide additional revenue.

To any one who has read the above post I'd like you to know I have edited it.
For the original figures for IBC tank annual fish production I used the "consevative" figure of 75kgs. This is not conservative it is, more likely, impossible so I have altered it to 40 kgs annually and adjusted other numbers accordingly. I hope nobody has blown a fuse and called animal protection on me;-)

IBC's are a cheap unit, I wont disagree with that. But square tanks are prone to accumulating solids in the corners, water swirl is impossible and IBC's arent made to last. Plumbing is expensive so compare the cost of setting up 10 IBC's compared to 1 x 10,000L AQ tank. Also that AQ tank is purpose made with conical outlet, insulated, made to last, has a large surface area for oxygen exchange and has a large open top for ease of harvest/grading etc.

In regards to grow area and footprint, media beds will never match DWC or NFT because with a media bed you need to be able to have access to all the plants over the entire media bed surface whereas with NFT or DWC they can be set on revolving platforms and be harvest at one end with the press of a button.

This vid better shows what I mean, try imagine this as one big media bed or even rows or modules of media beds.