Aquaponics?

[mamos]

Do we have any Aquaponic gardeners on thee forum.

For those of you that don't already know, aquaponics is a kind of gardening where you use fish to supply nutrients to your plants and plants to filter the water for the fish.

The fish produce ammonia from their gills and their urine which is poisonous to both fish and plants. Two kinds of nitrifying bacteria build up in the system that convert the ammonia into nitrites and then nitrates which feeds the plants. The water that goes back into the fish tanks is pretty clean so the fish are in nice clean water.

The practical upshot of all this is you can have fantastic plant growth and edible fish so you end up with a complete meal from your garden.

We are hoping to build a simple aquaponics system in our dome when it is complete and then a larger system next year when we have a little more experience.

Here is a short video explaining it a bit more

https://www.youtube.com/watch?v=7nIL9hWW3-Q

paul

[Green Aura]

I've been looking at it for a couple of years now, but I don't think it's a goer up here, although I'm not entirely sure why I decided that.

We have a loch full of brown trout spitting distance from our house, but you have to pay to fish on it.

[mamos]

Is it possible to embed a video into this forum or do I just do a link as above?

Paul

[Green Aura]

I'm not sure, Paul. I think people have in the past but I'm not very techy. I'm sure someone will be able to tell you how but in the meantime post a link.

[Odsox]

I have to say I've not looked into Aquaponics too deeply, mainly because I can't see it working.
On the other hand I have four Hydroponics systems operating here, with the first one running continuously now for 7 years, so I do know a bit about hydroponics.
It does sound a perfect system, with plants cleaning the water for the benefit of the fish and the fish "fertilising" the water for the benefit of the plants. But I'm pretty sure it's not that simple.
The only system I can see working is where the foul water is "watered" onto plants growing in soil, but not growing plants in inert media with the water recycled.
For instance vegetable plants need a wide range of trace elements and brassicas (for instance) need high levels of nitrates, which would not be produced in high enough concentrations by a small quantity of fish. Which means either the plants would be stunted or you would have to add extra, but ONLY THE EXACT AMOUNT the plants would absorb at that time, or the fish would suffer from high nitrate levels and the fish tank would become a pea soup of algae.
When I grow cauliflowers in my hydro I have to add a largish quantity of magnesium (Epsom Salts) once a week to prevent leaf tip burn which I'm sure would be detrimental to fish. The Epsom Salts I add to the tank is enough for 7 days, if there were fish to consider I would have to add it daily in exact quantities, the same as the nitrates.
So I'm sure if totally necessary it could be done, but it would be far too complicated and time consuming for me, and as I'm not that keen on fresh water fish anyway, I'll just grow my fruit and veg on their own.

If you do decide to give it a go, please let us know how you get on .... and hopefully prove me wrong.

[mamos]

I do go onto a couple of aquaponics forums and I am also in touch with Sylvia Bernstein who is a leader in aquaponics in the states.

Do you mind if I quote your post above to see if I can get some answers for you?

paul

[Odsox]

Do you mind if I quote your post above to see if I can get some answers for you?

By all means Paul, I am more than willing to be persuaded otherwise.

[diggernotdreamer]

I was more interested in the Medieval carp ponds, you could make modest sized pools and rear carp in them, the ponds would be dried up and cattle could be kept there and their manure provided weeds for the next batch of small fish to feed on. I have the room to make pools and it is something I have been thinking about for some time, esp as we are now pescatarians

[doofaloofa]

We have a big pond/small lake

At the present time it supports stickleback, and at least one koi carp (we put in 20 or so, but the otter came to visit, repeatedly)

I haven't found any edible water plants suitable for our temperate climate

I'm keen to stock it with common carp, as pig food if it doesn't taste nice, but can't source fry.

I fed the sticklebacks to the pigs last year, and they didn't complain

[mamos]

This is what Sylvia Bernstein said to Tony's post.

HI Paul. I'm laughing because that is exactly the kind of skepticism I had when I first got into aquaponics. I came from a 7 year background in Hydroponics via running the plant grow lab at AeroGrow, international in the development of the AeroGarden. I actually have my name on some patents for hydroponic nutrients, and I was convinced that there was NO way that it could be as simple as aquaponic practitioners said it was. But what I had lost site of was that a media-based aquaponic system is actually closer to a soil garden than a hydroponic garden. Because the "nutrients" are natural animal waste there is no need to "balance" them. And just as you don't worry about supplementing magnesium in your soil garden (or at least I don't...) you generally don't need to worry about that in AP. We grow a wide variety of crops, and never replace the fish water. We just make sure the pH is kept in proper range, and that we bring it up when necessary with natural calcium and potassium carbonate. The only thing we find we need to regularly supplement, aside from adjusting pH, is iron. The maintenance is far less than hydroponics because we don't ever replace the water in the system, which hydro guys need to do every few weeks.

Believe me, and thousands of others who are successfully growing organic fish and veggies across the world - it really works!

Paul

[Odsox]

OK, I stand corrected.
I will now have to spend some time Googling to see what I'm missing (and misunderstanding)
It's a good job we have 2 thoroughly wet days forecast.

[Odsox]

Right, well I did some Googling and I can see that it would be difficult for me to convert any of my hydroponics setups to aquaponics.

My greenhouse hydro system consists of 2 x 6" diameter pipes about 16' long which contains about 200 litres of media (sorry about the mixed measurements). It seems I would need a 1000 litre IBC for the fish to live in and there is no way I could get a cubic metre tank into my greenhouse.
I have a single pipe in one of my polytunnels and the same problem would hamper me there with it's 2' 6" doors.
Add to the fact that the only fish stock I could find in Ireland sells trout fingerlings in multiples of 1000, and they are about 200 miles away, and it all starts to become not worth the hassle.

I must agree that it's all very interesting though and were I to start again, I would certainly look into it a lot deeper.
There are some unanswered questions though. All the systems I found were all established and I could find little details of what the plants feed on while the fish were very small and what cleaned the water when the plants were very small.

The maintenance is far less than hydroponics

I would have to disagree there. My system allows me to go away for 7 to 10 day breaks, I think the fish may well be a bit hungry by the time I got back.

[mamos]

Just a quick reply from Sylvia about trace elements

Thanks for your kind words.
In general the answer is "yes, the trace minerals come from the fish feed", but sometimes deficiencies do occur and if that is the case we recommend a rock dust product called Aquaponic Elements. It works like a tea bag that you place under the water-in spout in your grow beds and it slowly releases trace minerals into your system (without the extra nitrogen and sodium that AP systems don't need).

And a mention about epsom salts and AP from Alex Veidel

Also, magnesium sulfate, or "epsom salt", is quite safe for fish. There are plenty of successful aquaponic growers that use it in their systems; I've also used it in mine. Like Sylvia said, trace elements are mostly provided by the fish food, but if it's still a concern, you can use water soluble kelp powder to provide what you need as well as give you some extra potassium.

I admit that AP might be for everyone but I am glad you had a second look at it Tony

paul

[mamos]

I have bought a couple of IBCs from Gumtree and I may have a chance of another one or two as well.

The plan is to build a simple solar powered single IBC aquaponics system this year as a learning aid to building a bigger system in the future. I can use the other IBCs for temperature regulation.



Paul

[mamos]

After being let down by a completely greedy git on Gumtree I have decided to not use IBCs at all and custom build my sump tank, fish tank and grow beds.

I was going to completely bury the sump tank and I thought what is the point of digging a big hole and then putting an IBC in it when I could just buy a pond liner for a fraction of the cost. We have very shallow topsoil and a hard shale subsoil so trying to dig down a metre to bury an IBC might have been a chore. If I go for a pond liner I can dig down as far as is practical and make the size of the hole equal to 1000 litres. So if I can only go down 500mm then I can make the hole 1000mm x 2000mm x 500mm for example.

The fish tank can be built half in the ground and built up with wood and the growbeds can be at ground level built out of wood and pond liner.

Can you see any problems with this plan?

Paul