Backyard Aquaponics
A place to discuss aquaponics

I'm getting some crayfish next month, about 10 pcs.
Astacus Astacus is the indigeneous species here and it tolerates almost freezing water.

My next step up is a system with crayfish, Sturgeon and Trout.
All tolerate the cold.

I want to put up a polytunnel with two 0,5m deep, 1,2 meter wide and 8 meter long troughs and a big 1,5x3x1,5m fish tank. I'll probably make one side one long DWC and the other side 4 meter DWC and 4 meter media bed to accommodate tomatoes, peppers etc. I can fit this into a 10x3 meter footprint.

Crayfish in one DWC, Sturgeon in the other and Trout in the FT.

FT will drain into the troughs via a SLO and a simple solids settlement filter. Crayfish and Sturgeon do a very good job at keeping the bottom of the DWCs clean. The pump will draw from an underground 1000 L sump tank at the opposite end of the DWCs from the FT, lift the water up to the top of the tunnel where it will run through horisontal NFT pipes back to the FT. Much like the setup I have now, only reverse order between DWCs and NFT pipes.

That will be a total of around 15.000 L including the sump tank and solids filters.

I'll put it all halfway in the ground to help keep temps stable throughout the year, and use a fairly low tunnel to minimize the volume of air to keep warm/cool.

I think the volume of water will allow for enough animals that I can actually hook up another tunnel to the system if I want/need to. That could be where we keep the citrus trees etc.

My goal is to first supply almost all of the veggies my family of 6 needs along with seafood, which we all love.
Second, we will sell surplus at growers market and a small barn door stall to supply the local community.

Ultimately I want to provide for our family by producing and selling high end veggies and seafood to restaurants and discerning families. I have a whole chain concept in mind!


These ones are really cheap here. A 10 meter long tunnel this model is only around 700 USD.
I can then build an insulated solid wall in one end where the FT sits and have the possibility to open up the entire end for easy harvesting of the rafts.




Hmmmm, got a little carried away there.....

- Jens

System summary at this point - moved from another topic to consolidate the information

My first system is in a 1,85 x 2,5 polysheet greenhouse.

FT is a 470 L aquarium sourced from my living room.
2 settlement tanks are 70 L multi boxes. That's what we call them here anyway.

DWC troughs are brickie bins, 90 L each.

Media beds are cut down brickie bins.

Pump is the filter pump for the aquarium. 3500 L/H @ 1 m head.

Total water volume around 700 L.

25 goldfish and around 10 others and a dwarf crayfish. A few snails and 25 Amano shrimp.

All wood, the black legs etc. are reused materials.

I'm not sure about your native crayfish but ours are cannibalistic. I'm glad you won't be putting the crayfish anywhere the trout can get at them and the sturgeon might like their appetizers with claws as well .

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I have some reservations about the plan and how you're handling solids and the circulation. The simple solids settlement area will usually take up more space than some other type of solids filter and I just want you to know this is a disadvantage in most systems (maybe not yours).

The other thing that wasn't clear is where in the flow your media beds will be. Right now it's tough to see how solids will be adequately eliminated so that they won't either foul the plant roots or cause problems for the fish.

Scotty, thanks for moving my post.

I actually wanted to add that post to the pictures of small systems thread, but by mistake made a new topic.


Our crayfish are cannibalistic as well, but as long as they have hiding places abound (tubes) they co-exist without too many losses. Actually, some small time breeders throw the leftovers and shells into the pond when they have eaten a batch, letting the remaining feed on the scraps. And they live in high densities in ponds.

I'm not sure how much filtration I will have. From Friendlyaquaponics I have gleaned that if the fish food is fine enough (as in not coarse), then you actually don't need to filter the water. Especially if you keep animals in the troughs who clean up (shrimp, crayfish, sturgeon). Therefore I hope to be getting away with a simple settlement filter like I'm running now. Anyway, that's what I'm testing now.

Since posting this I actually came up with the idea of keeping two separate systems. One with FT -> DWC -> ST -> NFT -> FT and one with FT -> GB -> ST -> NFT -> FT. The growbed system would then be running water chemistry balanced for fruiting plants ie. high in Potassium and Calcium and the DWC would run low on those things for leafy greens etc.

They would still sit side by side in the same polytunnel.

Incidentally, yesterday I fixed the flow issues I had in my GBs and now the pump can run at full tilt and the flow thru the whole system can keep up.

Tomorrow I'm getting a host of different seeds in the mail, so it's seeding time!
Can't wait to have the entire system filled up with produce coming up.
Then I can start feeding the fish again!

Since my rebuild last weekend the system had a setback on the bacterial side and Nitrites went up to 0,25 and Nitrates to 50. Now they both seem to be coming down again, and so is PH.

Cheers - Jens

- Jens

Hi Jens,

The system with this layout - FT -> DWC -> ST -> NFT -> FT needs some additional filtration between the fish tank and the DWC or I think you'll have problems with the roots fouling eventually. The crayfish or sturgeon may be enough to help with this, I haven't tried it so if you decide to try it, it will be interesting to see if it works for you over the long haul.

I Will install a settlement tank of some sort like a 55 L blue barrel or similar, which can easily be upgraded to a swirl/media filter should the need arise.
I'm still hoping the crayfish will keep it tidy, though.
Anyway, this build is not until next summer so I will probably change the design many times before then. :-)

I really appreciate you input Scotty.
It seems to me we have similar climate in Denmark and Oregon, so I'm following your system and experiences.

Cheers

I have to admit I'm wondering about the crayfish in the DWC... my yabbies rip up and eat any plants I put in with them, so I think they'd have a lovely time eating all the roots in a DWC bed!

That's why I'm making the troughs 50 cm deep.
I've seen some vids on YouTube where people have done it with success.
If they don't behave I will put them in the sump tank and put mini shrimp in the DWC.

I've seen this display a couple times here, what's the sensing platform?

Does it provide remote sensing?

Nothing fancy I'm afraid.
It's just jbl Proscan measuring strips.
Your phone then has an app which reads the colors of the strip and gives you the results.

https://www.jbl.de/en/proscan

So nothing really fancy. It's just easier than comparing the colors yourself.

Cheers -Jens

So I build a new trough and fish tank I want to show off!




I used a 1,2 mm epdm pond liner and 4 lengths of 2x4 and two sheets of 30mm styrofoam as the only new materials.
All the boards are repurposed pallets.

Total volume is almost 1000 liters in addition to the approx 550 liters in the aquarium and sump.

Ooh, nice! Looks very neat and tidy.

Thanks Mel.

Now I just have to rebuild the other side.

I'm going to make a large sump tank and then make a trough for my media bed the same style as this DWC trough. But that's for later in the season when the tomatoes are dying anyway.


Cheers - Jens

Update time!

Everything is growing really well now!
We have had a very warm September which has helped me see some results in spite of my late beginning and many rebuilds.

Looking good!