Recirculating or Non-Recirculating?

[GaryD]

Hi,

A recirculating aquaculture system is one where the water is pumped from the fish tank through a bio-filter and back into the fish tank.

In an aquaponic context, bio-filtration will usually be provided by a grow bed filled with media like gravel or expanded clay (rather than a stand alone bio-filter).

AP purists will insist that it's only Aquaponics if this recirculation is a feature of the system.

My view is that, since Aquaponics is the combination of Aquaculture and Hydroponics, any combination of the two can be used in the development of an Aquaponics system.

In its simplest form, Aquaponics might be nothing more complicated than duckweed floating on a fish tank. The duckweed removes nutrients from the tank (to the benefit of both plant and fish).
The next level of Aquaponics may comprise plants floating on a polystyrene raft in the fish tank - with their roots dangling directly in the water.
In yet another variation on the theme, we can have a fish tank with a trickling bio-filter (in which nitrification occurs) supplying nutrient-rich water for use in a variety of growing systems......all of which are independent (ie.....they do not recirculate) of the fish tank. Some of the largest commercial aquaponics systems operate on this premise.
At the end of the spectrum, we have the recirculating aquaponics system where the water from the fish tank is pumped out through the growing system before being returned to the tank. This variation on the aquaponics them has two variations to it.......those system which use the growing system (usually gravel grow beds) as a bio-filters and those which employ trickling bio-filters to provide nitrates for other types of growing systems including Nutrient Film Technique (NFT) or Deep Water Culture (DWC). The largest commercial recirculating aquaponics systems are usually of the NFT or DWC type.Options #4 and #5 represent, between them, the overwhelming majority of aquaponics systems. Both of them offer distinct advantages and since no one growing system is suitable for all plants, it's likely that most AP enthusiasts will eventually use both systems.

GaryD

[njh]

Hi,

A recirculating aquaculture system is one where the water is pumped from the fish tank through a bio-filter and back into the fish tank.

In an aquaponic context, bio-filtration will usually be provided by a grow bed filled with media like gravel or expanded clay (rather than a stand alone bio-filter).

AP purists will insist that it's only Aquaponics if this recirculation is a feature of the system.

My view is that, since Aquaponics is the combination of Aquaculture and Hydroponics, any combination of the two can be used in the development of an Aquaponics system.

In its simplest form, Aquaponics might be nothing more complicated than duckweed floating on a fish tank. The duckweed removes nutrients from the tank (to the benefit of both plant and fish).
The next level of Aquaponics may comprise plants floating on a polystyrene raft in the fish tank - with their roots dangling directly in the water.
In yet another variation on the theme, we can have a fish tank with a trickling bio-filter (in which nitrification occurs) supplying nutrient-rich water for use in a variety of growing systems......all of which are independent (ie.....they do not recirculate) of the fish tank. Some of the largest commercial aquaponics systems operate on this premise.
At the end of the spectrum, we have the recirculating aquaponics system where the water from the fish tank is pumped out through the growing system before being returned to the tank. This variation on the aquaponics them has two variations to it.......those system which use the growing system (usually gravel grow beds) as a bio-filters and those which employ trickling bio-filters to provide nitrates for other types of growing systems including Nutrient Film Technique (NFT) or Deep Water Culture (DWC). The largest commercial recirculating aquaponics systems are usually of the NFT or DWC type.Options #4 and #5 represent, between them, the overwhelming majority of aquaponics systems. Both of them offer distinct advantages and since no one growing system is suitable for all plants, it's likely that most AP enthusiasts will eventually use both systems.

GaryD

I agree with you 100% gary, except... what is #5 again?

I think the term aquaponics is a) rather stupid (as aqua and hydro both mean water) and b) too narrowly defined.

Having realised that a great way to warm up your nitrifying bacteria is to wee in water before you add the fish, I propose a new term "Piscinponics" rather than 'aquaponics'.

Furthermore, I would like to extend to complete systems design involving fish, chickens, in ground, satelite and recirculated hydroponics, high performance solar design and low impact energy use as holistic Mollison-like design; or HoliMolli for short...

[GaryD]

Hi njh,



I agree with you 100% gary, except... what is #5 again?

I think the term aquaponics is a) rather stupid (as aqua and hydro both mean water) and b) too narrowly defined.

Having realised that a great way to warm up your nitrifying bacteria is to wee in water before you add the fish, I propose a new term "Piscinponics" rather than 'aquaponics'.

Sorry 'bout that......I meant #3 and #4 (or perhaps I was subconsciously anticipating the arrival of your "piscinponics" concept.

In point of fact, "piscinponics" already has a precedent in Aquaponics - under the much more mundane name of nitrogen dosing.

In essence, it means using any nitrogen source (other than fish) to get an aquaculture system to cycle. Nitrogen sources may include pure ammonia, fish food, prawns (cooked or raw)......or urine. Personally, since I prefer my fish with less of an Indian flavour, I'd opt for the prawns.

In any case, nitrogen dosing is a more effective means of cycling a system than using live fish and it has none of the ethical issues.


Furthermore, I would like to extend to complete systems design involving fish, chickens, in ground, satelite and recirculated hydroponics, high performance solar design and low impact energy use as holistic Mollison-like design; or HoliMolli for short...

I agree with you entirely. While I refer to it as Integrated Backyard Food Production, I think HoliMolli has a nice ring to it.

I hope you're planning on staying connected while you're overseas.

Gary

[nogreenthumb]

in hydroponics....where does the nutrient come from to feed the plant?

[Murray]

In Hydroponic systems you go off to the hydroponic shop every week or so and spend a small fortune on various chemical brews, mix them up and add them to the water.
Hydroponics works well, grows good looking stuff, but some folk are finding the chemicals required becoming increasingly to expensive.
Still other folk are finding the use of "Chemicals" not ideal.
The Hydroponic industry is now producing what they call "Organic" chemicals. I don't know how they do that.
One visitor who came to see my aquaponics system recently, has been doing Hydroponics successfully for years. He is switching to Aquaponics because of the increasing cost of the "Organic" chemicals, and he is feeling increasingly uncomfortable about the use of such chemicals in his hydroponic system.
The switch will not be that difficult, he has purchased a 2300 ltr tank and a couple of 585 ltr grow beds. After the fish water has been through the grow beds and run back to the sump, he will then run the still nutrient rich water via his hydro trays/troughs. From there the water will run back by gravity to the fish tank.
It will take a little while for him to get everything into balance, but given the right attention he will have a fantastic "organic" vege growing system. And I almost forgot .......Fish to eat as well !!!!
What a great idea.
Muzza

[nogreenthumb]

Hi,


My view is that, since Aquaponics is the combination of Aquaculture and Hydroponics, any combination of the two can be used in the development of an Aquaponics system.
GaryD



so then this is not strictly true as aquaponics doesnt use hydro chemicals?

[GaryD]

Hi,

It's true inasmuch as it takes the fish rearing aspects of aquaculture and the growing systems of hydroponics. It doesn't need hydroponic chemicals because they are largely provided by the fish.

Gary

[nogreenthumb]

ok got stuck on "ANY combination of the two CAN be used"

[Frank]

In Hydroponic systems you go off to the hydroponic shop every week or so and spend a small fortune on various chemical brews, mix them up and add them to the water.
Hydroponics works well, grows good looking stuff, but some folk are finding the chemicals required becoming increasingly to expensive.
Still other folk are finding the use of "Chemicals" not ideal.
The Hydroponic industry is now producing what they call "Organic" chemicals. I don't know how they do that.
One visitor who came to see my aquaponics system recently, has been doing Hydroponics successfully for years. He is switching to Aquaponics because of the increasing cost of the "Organic" chemicals, and he is feeling increasingly uncomfortable about the use of such chemicals in his hydroponic system.
The switch will not be that difficult, he has purchased a 2300 ltr tank and a couple of 585 ltr grow beds. After the fish water has been through the grow beds and run back to the sump, he will then run the still nutrient rich water via his hydro trays/troughs. From there the water will run back by gravity to the fish tank.
It will take a little while for him to get everything into balance, but given the right attention he will have a fantastic "organic" vege growing system. And I almost forgot .......Fish to eat as well !!!!
What a great idea.
Muzza

So if this is true, why don't you sell kits just using hydro channel thingies.

Why all the square beds like in the O'dee setup? Why do we still need the square beds at all, why do we need two 525ltr growbeds exactly.
Is that like half the growbeds to fish tank plus hydro channels?

And how many hydro channels and veges could you get, or would you need for a 2,300ltr fish tank and two 585ltr grow beds?

And how many fish?

Surely the cost of the hydro channels would be cheaper than the kit beds?

Can you, or can you get your friend to post some pictures of the setup Murray.

I'm confused. But it sounds like the way to go

[Murray]

Frank,
Ther is just so many possible ways that Aquaponics can be done. The one thing that cannot be avoided is a bio-filter to convert the ammonia etc into nitrates by the use of the good bacteria that sets up and resides in the bio-filter.
In the gravel grow bed model, the gravel grow bed/s are the bio-filter.
The use of gravel grow beds has another benifit as well. The solid waste from the fish goes into the gravel grow beds and settles down through the gravel and is used up by deep rooted fruiting plants such as tomatoes. Earth worms have taken up residence in my gravel grow beds. I did not put them there. I imagine they are feasting on the solid fish waste and any dead roots that may be left in the beds from previous plantings. The benifit of the worms being in the gravel grow bed goes without saying.

What an amazing little eco system has been created ! It never ceases to amaze.

If you do away with the gravel grow bed/s then you need to have an actual bio-filter. You also need to filter out the solid waste and do something with it. You could throw it into your compost bin perhaps.
In large commercial systems the disposal of the solid waste can become a problem.
For the home Aquaponist I believe that the gravel grow bed model (with some possible variations/additions) is the best way to go. They (the gravel grow beds) make good use of the solid waste and act as very convenient and efficent bio-filters.
In other words, you have a bio-filter/s that you can grow plants in. That's convenient !!

Muzza

[Frank]

OK, so the 525ltr growbed with gravel is the bio-filter, I get that.

But how many hydro channels and how many plants can a gravel biofilter support?

In the example there is two 525ltr gravel bio-filters. So how many plants and how many hydro channel thingies does this support?

[GaryD]

Hi Frank,


So how many plants and how many hydro channel thingies does this support?

Far more than you'd need for a backyard operation. You'd be limited by the amount of water that would otherwise have flowed back into the fish tank.

Nutrient Film Technique (NFT) systems only have a thin flow of water through the long plastic troughs.

Deep Water Culture (DWC) systems would use a heavier flow. DWC systems are probably a better choice for backyard food producers.

Gary