Backyard Aquaponics
A place to discuss aquaponics

Hi All,
Firstly, thanks for all the guidance and information you are all contributing to this forum!

I’m looking to setup an aquaponics system in London – UK, but my wife insists it needs to look good as part of the garden – ie no ICB’s showing, no blue barrels etc. So my plan is to have a semi raised fish pond, part in the ground, part above. The above part, must have a viewing window for my wife and kids to see the fish (wife’s requirement).
Where I live the temperature outside can go down to -3, -4 for short periods, hence I’m wanting part in, part on the ground.
My family do NOT eat fish, so they would be there purely for the garden, and I’m unlikely to remove over the winter period – I have nowhere else to home them… (I’d really like to leave them in situ all year round for this reason!)

My plan is (where the letters are, is where I have questions)
1) dig a rectangle frame – aprox 30cm wide covering an area of 5m long, 1m wide, 30 cm deep
2) Fill this with concrete to act as the frame for above ground.
3) Dig out the centre of the concrete frame to unknown dept (A)
4) Build up from the concrete frame 1 railway sleeper high all round as the base above ground
5) Next layer, cut out to include a window (B)
6) Remove any sharp edges in the inside of the pond.
7) Attach 50mm solid insulation to the sleepers the bottom of the concrete (C)
Sandwich pond liner around the top, with final layer of sleepers.
9) My intention for the grow beds is then to make two raised beds on top of the pond, so they COVER 1/3 of the pond each. This will leave 1/3 of the 5m length open to the elements, and 2/3 covered and in darkness. – from left to right this would be approx. 160cm grow bed, 160 cm open, 160cm grow bed.(D) Water would be pumped up from the outer edge of the pond into the grow bed, and fall back into the pond at the open end from a high of say 20-30 cm. (I’m looking to design something where I can roll the beds so can get to the water underneath for maintance and cleaning etc)
10) There will also be a water feature – a water fall from the back falling into the pond (wife’s requirement). (E)
11) Lastly, there will be a trellis running along the back of the pond to allow climbing plants (tomatoes, beans, peas etc) to grow up.

Questions:

A) So pond will be approx. 40cm above ground, how deep should I go underground? (remember fish will be in here all year round!)
B) Any ideas how to recess window with pond liner? Will this add to issues with keeping temperature up? I’m thinking approx. 20cm high (one sleeper), by 100cm long
C) Should I insulate all the way down to the bottom of the pond? Or just to the bottom of the concrete frame?
D) Will this cause problems for the fish – if only 160cm of open area is available?
E) Will three areas of water falling in cause distress for the fish if in the open area? And will this be enough water movement to avoid a pump for air into the pond?

So general idea is above, any tips/suggestions/answers for my concerns?

The tank will be approx. 70cm wide, 4.8m long and poss 1m deep – roughly 3220 litres if I calculated right, but initially will only have a few (3-4) fish while I get setup with the whole system.
Eventually im aiming to pipe water off to other parts of the garden (once i have built a garage) for other plants (strawberries etc) so i'm aiming to have one pond to cover the lot, by adding fish as i expand.

A) the more water you have the more stable a system is and the happier your fish will be. Forget a little about the focus on insulation, your grow beds are giant radiators equalizing temps with the environment, unless you cover the whole thing in a greenhouse it won't make a huge amount of difference..

B) Personally I wouldn't bother with the window, you're only 40cm high anyway, you'd have to lay on the ground to get a good view in.

C) Grow a fish species that does't mind the cold, better than fighting it.

D) NO, fish don't mind cover they often seek it out, but I think having so much tank covered could be a hassle. If anything goes wrong, fish is dead up the back corner and even if your beds slide, what if you have plants growing up the back trellis, you have to roll the trellis as well?

E) No, fish don't mind water falling, it should be enough air though you'd want to think about water flow moving the water around, water can get stagnant in a long skinny tank perhaps with dead spots at the ends.

Thanks for the feedback, with regards to A, i may try and make some removable cover type setup in the future if growing goes well so i can keep some produce over the winter, but for at least this year it will be open - i guess it may be a case of testing this year to see if it does get too cold or not!
B) I dont want to either - wife dictates otherwise - i may rough build it and then see if i can get her to change her mind...
C) I was thinking goldfish - any other suggestions?
D/E Im now thinking of having a total of 5 pumps - one on each end to bring water up to the grow bed (constant), and another two surface mount to push water surface around on the ends into the centre (timed say on for 15 min every hour). Then a third to suck up from the centre for the waterfall (ad hoc). Hadn't considered to plants on the trellis! may be i'll have to raise the grow beds up another layer and have a hatch type setup to open and inspect... More thinking needed for this one.


Any other thoughts or tips?