Backyard Aquaponics
A place to discuss aquaponics

I have seen a commercial system of a guy now retired from selling fish and cucumbers where all solids are removed. Fresh water is added daily to replace the water taken when the solids are drained out of the tanks. The fish water is kept very clean and is only for growing fish. The waste water is sent to a 3 tank septic tank where it is anaerobically digested in one compartment then aerobically digested in the next. The third chamber is an over flow which gets pumped to the gravel beds. This water grows veggies like mad and all the minerals ect from the food available. No supplements are added and the plants out preform anything I have seen in my systems.

This approach makes sense though, best possible growth conditions for fish in one place, and grow food in another place where growing conditions are maximized for plant growth.

So the lettuce pictured are the second crop of lettuce....

Any pics of the first crop Tony??..... how long did they they take from seedling to harvest?... and what sort of weight??



.... I think you'd better refer to the setup as a "pilot" setup, or proof of concept... rather than a "commercial setup" Tony...

It's soooo far away from a commercial setup... even my mega system was bigger than that... and my system wasn't even close to a "commercial system"....

And could you give a breakdown of the production figures quoted in the newspaper article Tony...



Given the minimum time taken to grow a lettuce from seedling, in optimal conditions is at least 4 weeks....

You'd need to be producing 666 lettuce per month to acheive 8000 lettuce a year...

My tables in the above pictures are 10 x 6mtr, with a hole spacing of 200mm for each table.... a combined total of 400 holes (2 x tables... 20 x 6mtr)...


And your tables appear to be spaced at least 300-400mm between holes... which only gives you about 160 holes per month, or about 2000 per year...

And assuming your growout weight for the trout is around 500-600gm.... and would take about 4-6 months....

With 350 trout... that's a potential harvest of 210kg (@ 600gm).... two harvest a year... lets say 450KG... AT BEST...

And that's if you can both... obtain trout fingerlings for a second crop... and can keep them alive, and growing through summer...

Thats a long way short of 600kg of fish, and 8000 lettuce per year...

I know you're well intentioned Tony... and we'd all like to believe that aquaponics will feed the world...

But making "inflated" claims as to yearly production... and/or the viability of "commercial" aquaponics.... just doesn't help the cause.... or add up in reality....

A commercial (breakeven) hydroponics setup requires about 40,000 holes... minimum....

We harvested 576 plants every 4 weeks at our peak, that's with over 2300 holes in the two systems. Some rafts were taking longer than 4 weeks but we were experimenting with plant varieties. But peak production with that number of holes was under 600 plants a week. We really need to get ours up and running again to get an average production level over 12 months..

My early estimation for viability on a system like ours was that you would need at least double what we have down the back, and you would have 1 person full time, with another part time.

Time to get a cover sorted for our system.....

That sounds about right Joel.... but...



Don't you mean... 600 plants a month???


By the time you allow for crop rotation/staged growth....

To harvest 8000 lettuce per year.... you'd need at least 5000 holes

Of course I meant that......

Hang on...? So you're only getting 1.6 lettuce per hole per year?

If you need to harvest about 1000 lettuce each month... you need about 4000-5000 holes...

For the various stages of growth... and losses...

i.e ...

1000 holes... plants 1 week old
1000 holes... plants 2 weeks old
1000 holes... plants 3 weeks old
1000 holes... plants 4 weeks old

Allow another 1000 holes... plants 5-6 weeks old... (slowed growth, seasonal factors)...

Just rough figures...

OK... assume no losses... then its...

670 holes... plants 1 week old
670 holes... plants 2 weeks old
670 holes... plants 3 weeks old
670 holes... plants 4 weeks old

Allow another 670 holes... plants 5-6 weeks old... (slowed growth, seasonal factors)...

At least 3,500 holes....

Hang on, changed my mind on the previous one. I was right at under 600 plants per week.

At peak, we were harvesting 4 rafts from each system, each week in a 4 week cycle, 16 rafts in each system. That's 8 rafts each week with 72 holes a raft, makes 576 lettuce each week, or 2300 per month.

But note that is peak, we didn't keep it going at this level as it was too much work without having a decent market for produce. And we starting running into the growth issues from excess leaves in the system not long after hitting peak production.

Rupert,

What a surprise and lovely to hear from you again.

Now to try and answer your concerns.

Your little dig at me in calling it a commercial system when the title of this thread and indeed every reply to the thread has the heading "Pilot Commercial NFT System" is unnecessary. I believe it is self evident that it is just that a Pilot Commercial trial. At no stage have I suggested that a single system ( 5000 litre tank, sump tank, filter system and 16 x 6 metre NFT channels) was commercial on its own. We are testing two of these systems.
The term Pilot Commercial means that the system itself is tested and if the trials succeed then the whole operation can be scaled up to a commercial level with appropriate changes made on the basis of the trial.
Secondly the spacing between each lettuce is 250 mm not the 300 to 400 mm you claim they are. This means that each system has about 384 holes. If we were harvesting every 4 weeks then in a year the system on its own can produce 4992 lettuces per year (but I have rounded it down to 4000). Yes I know you can't harvest all the lettuce at once without nutrient build up in the system and I will explain later what happens.
Getting back to the system which consists of the 5000 litre tank. At 30 to 35 kgs per cubic metre (1000 litres) the system has the potential to produce 150 kgs of fish every 6 months or 300 kgs per year ( and 4000 lettuces).
So where did the Australian get 600 kgs and 8000 lettuces? The journalist simply combined the two tank systems productions as we are testing two systems at once. Yes it would have been better if I had seen a draft and I could have corrected that error but I wasn't so the story ran.
If the system proves satisfactory then it is our intention to set up a much larger system which will consist of the following. There will be 4 x 5000 litre tanks each with their own filter system but all four tanks will train into a common sump tank (also 5000 Litres).
The submersible pump will then pump the water back to the four tanks and also to the NFT channels which drain directly into the fish tanks.
In effect what I am trying to do is emulate the UVI raft system but with NFT channels. Thus a tank of fish would be harvested every 6 weeks (or each tank would take 24 weeks to harvest date) Each tank which has 16 x 6 metre NFT channels running into it would also have the lettuces harvested every four weeks. As all the tanks drain into a common sump tank(as the UVI system does) then there will be enough nutrient for the next lot of seedlings which would be planted as soon as the 16 NFT channels are harvested.

Will it work? I believe it will and we intend to set up a larger system at Murdoch horticulture centre. They have given us access to a fully covered, large greenhouse.
As for the fish I can get access to barramundi for our hatchery in Fremantle all year round. I have a few ideas on how to ensure the water is at least 24 C all year round without resorting to using electricity. Time will tell.

Sounds great Can't wait to see the no electricity heating system, Barra year round could be profitable, unlike trout which the knockers state sells too cheaply to be work while.

Best of luck

But your advertisement for your upcoming "workshop" clearly stated that it "will include a site visit to the commercial setup."....

If I turned up at the workshop expecting to visit a "commercial" system.... I'd feel it had been misrepresented...

While I was in no doubt from the title... that was indeed a "pilot" system Tony... it is no more than that... and at this stage couldn't even be claimed to have proven "commercial" viability...


Happy to accept the above Tony... from the naked eye the photos appeared to have spacing larger than that...


And they're acheivable figures IMO... with a mix of trout, and as you indicate... Barramundi... with the necessary temperature controls...



Explaination accepted... and understood.... and I'm glad... for too many grandeoise claims have, and are made about the commercial viablity of aquaponics... and the water is beginning to become tainted...


Ok... so that would give you 1200kg of fish per year... and 16,000 lettuce...

Lets say you sell the fish at $15/kg... that's $18,000 per year...

You'd be lucky to get more than $1/lettuce... so that's 16,0000 lettuce @ $1... $16,000 per year...

A total income of $34,000 per year...

Which would hardly pay for the running costs, stock and labour...

Seriously... that's just no where near the scale of being "commercially viable"...

And in order to scale up to a point where it might be... involves massive capital expenditure in land, plant and stock... and labour... and processing facilities...

No change out of $750,000 - $1 million startup capital IMO....

And a ROI of over 10 years +...

Just to break that down... assuming...

Seedlings @ $0.10 ... 16,000 x $0.1 = $1600

Fingerling @ $1.00 ... 2,400 x $1.00 = $2400

FCR of 1.5 => 1200kg x 1.5 = 1800kg of feed

Feed 90 bags (20kg) @ $60/bag = $5,400

Power...

4 fish tank pumps, 4 filter pumps, 1 sump pump, 1 air blower... assume 200w each... running 24hr/year... 17520Kw... @ $0.15/kw... = $2620

Labour.. 1 person 50 x 40hr/weeks @ $20/hr...

Gives 10,000 hours @ $20/hr = $20,000

Total costs... $32,020 per year....

Total revenue... $34,000 per year...

According to Fisheries Data (compliled from the returns of licenced aquaculture production figures) Barra now only fetch an average of $10.58 kilo compared to Trout $10.16 so not much in it. With the large amount of fish coming onto the market from Cone Bay the days of getting $20 a kilo for Barra are over.

I was being both conservative... and generous... in my ballpark costings Troutman...