Backyard Aquaponics
A place to discuss aquaponics

Hi all

I'm all "new" to Aquaponics, but mighty impressed. Come spring (I'm in Sweden), I'll build my very first system, for sure. Been wandering around this forum and others, watching all the youtube videos I could find (not too many out there, come on!) and I think I got the concepts quite well so far. I've even been pestering my soon to be wife, as she's a biology teacher with all sorts of questions =)

Some thoughts do hit you when you start interesting yourself in something new, and it struck me that "we" do have an 85 cubic meter tank "lying around" (it's built into the ground actually). It used to hold urine, but could be cleaned, disinfected, covered and filled with water. I am aware this would be a huge system, but we have access to close by land aswell.

This would be a future system for sure,but one can't help to ponder..
How much fish could you fit in a tank this big?
How fast could/would it grow?
Could it be commercially viable to grow say tomatoes (easily grown here) with a tank this size stocked with fish you can sell?

If you have any input on this, it'd be most apreciated, as I'm trying to get the family interested in this =)

When spring comes, I'll be back with questions and updates for sure about my first system.

Thats a lot of wee!, won't have any trouble cycling the system heehee!

Thats a huge tank, If you are only intending on a "family sized system" is there a way you could "wall off" part of the tank to cut down the volume?

Welcome to the forum Bestcoast. and merry christmas!
Axl

best, IF you could provide enough plants and gravel the tank would support
between 2.5 and 5 metric tonne of fish

2.5 to 5 metric tonne of fish? A neighborhood fish-fry, for sure. Oh, you should be able to get 8-10 times the weight of vegetables that you do fish. You might consider starting a little smaller.

Welcome, bestcoast. Glad to see we got you thinking already.

The good thing is that you can use the added water voulme to give your system stability.

Jaymie has quite a few thousand litres and i'm fairly sure its not stocked to capacity. She is getting good growth so maybe we can get an estimated % of capacity she is running?

got any pictures of your "tank"

I've got 1:1 growbed to tank ratio, but with a reduced fish capacity.

20,000L : 10,000L should allow us 600Kg fish (1200), but we've only got 250 fish, so that is 20%

Wee, thank's for all the replies!

I know it would be a HUGE system, and I'm only considering a little for the possible future. These kind of tanks are around here and there on old farms, and I'm trying to find a farm to buy myself, so who knows. This tank belongs to my dad really.. Sectioning it off would be out of the question, but only filling it halfway would work fine. Raising 2.5 tonnes of fish would require a small factory I guess.. =)

I'm still curious how fast the fish would grow. I bet there's great difference inbetween species, but some kind of ballpark figures for eatable fish that can do away with northern hemisphere climate would be most appreciated. Would I need to decrease the # of fish as they grow to stay "within volume" (I'm sure we wouldn't complain about eating own-raised fish 2 times a week or so =) or would I make sure things "even out" as my plants grow?
My dad mentioned it would be quite expensive to heat the tank, so I'd like to look into doing seasonal "cropping" of fish and plants, and leave the system off during the hard winter months, then restart it 4-6 weeks before planting new veggies (and fish).. Would that work at all, would there be enough time during say April - Oct/Nov to raise fish decently sized to sell? I also guess I'll be needing a reliable pump, but I'm unsure how much flow I'd need. Would I need to change the fish tank once every 15 miutes, every hour, maybe just once evey day?

Like I said earlier, I'll be having a small system up come spring, and will prolly learn alot during that setup.. I'm a techie, so I'm aiming at building a system that has plenty of ingenious solutions, hehe..

Lots of questions bubbling out, but I figure that's what the forum is for, learning, right? =)

Wow, 50 tonnes of vegetables... I just commissioned a greenwaste plant that processes 50,000 tonne per annum. Based on the size of that plant... WOW 50t would be a huge amount of veggie.

Steve has convinced me, that it doesn't matter how much water you have if you are limited by GB. You don't need to limit your water to match your GB.
More water is better - more stability.
maximum stocking density = 1litre tank : 2litre GB. If you don't have this, just stock less fish. The extra water wont hurt, even if it's hundreds of times to big.

As for speed of fish growout. Depending on the variety, we have fish that grow edible size in 8 - 12 months, and some that take 18 - 24 months.

If you could source your fish at the start of spring, which are not fingerlings, but already part grown, you should be ok, but you've got a lot of research to do there.

I'm not sure how it'd go in your climate (especially in winter) but solar heating (black pipes on roof) show be able to raise the tank a couple of degrees, or above freezing at least :-)
If you could insulate the tank, and grew your veggies in a double glazed green house, you may be able to extend your growing time. Perhaps heat a little before spring and end of autumn (fall).
Heating is only expensive if there are large inefficiencies, like water open to bitter-cold snow laden air.

within reason, 2 goldies in an Olympic pool prolly wont cut it

Best, you could shut it down over the winter, but i'd much prefer to see a polly tunnel green house and maybe cold tolerant (trout?) fish for the winter.........

A system gets a magical sort of stability with time. (sounds like crap, but its true) I;d hate to see it start from scratch every year...........

I may be wrong, but with very low stocking density, I believe that the time to stabilise the system would be longer. (lower % NH3 requiring longer for bacteria to build up)

Merry Christmas,
Tony

Best

Since nobody else has asked, why do you have huge urine tanks in Sweden, or is this a septic tank?

Merry Xmas from OZ

Sleepe

Sleepe: We used to have milk-cows some 10 years back, and was required to separate urine from maneur, and then used it for fertilizing our fields.. My dad's been having all kinds of plans for it, ranging from swimingpool to garage =) I think my idea is the best so far anyway ..

But 50 tonnes of veggies would be waay to much. We'd run it for profit, but just enough to stay alive I guess. I doubt we'd be able to afford double-glazed greenhouses, but if "polly tunnel green house" means those tubular plastic-coated de-mountable "land-covers" they market for growing energy-forests (for making fuel), that's what I'm looking into. They are hard to get quotes on, but I bet they're expensive new.. I was thinking our maximum would be something like 500-1500 m2 of greenhouse, which would still yield something like 5-10 tonnes of tomatoes anyway.. It's far fetched to get started (investment) I guess, and would require careful planning.. I'll see if I'm still as keen this spring after building a small system, I'll look into further details ..

Anyway, while pondering about here I ran into a "Duckaponix" thread, and it struck me we've been having trouble keeping our duck-pond reasonably clean for years.. So you can imagine that project skipping ahead of my planned Aquaponics system.. Maybe I'll incorporate a fishtank here aswell, who knows =)

Thanks Best

You learn something every day (Never heard of that sort of requirement).

Gonna get flamed for this but why don't you start with Hydro vegies in poly tunnels and work up from there (good practice and not so many variables) Check out http://www.backyardaquaponics.com/forum ... .php?t=749

If you've no experience with fish try with a small fishtank and learn about cycling and fish problems on a small scale.

BTW 85 cu metre fishtank in your back garden , lucky bugger .

Sleepe's suggestion has merit, and hydroponics is convertable to aquaponics without too much trouble. Several folks have done that. The whole nitrogen cycle is the trickiest thing to understand imho.

Oh, I've got my head wrapped around hydro allrite. That's what led me here in the first place. Right now I've just got a simple self-contained E&F "herb garden" with just 6 plants right now, proof of concept kinda thing, running in a corner of my kitchen. I could post pics..?

I am also quite well into plant biology and natural cycles etc. What fascinates me the most about AP is the beautiful natural relationships between fish, plants, water and bacteria..

Steve: I can see what you mean, but more water would also mean a higher flow of water through the system, as more water needs to be cleaned per period of time, right?
I can also see, clearly, how a system would "gain" stability over time, for sure!