Backyard Aquaponics
A place to discuss aquaponics

One problem seen in large application of Aquaponics from an Aquaculture point of view is the area of plantspace required to clean wastes for a volume of fish.

We deal in smaller numbers but scaleability is quite possible using math and good design.

This is where towers will help a great deal.

For this example lets use 24 Kilos of fish. Also for the example let's suppose water depth is 600 mm and stocking density is a nice humane 4kg per 100 litres.

This means 1m2 pond of 600 mm depth is holding our 24 kilos fish at a density of 4 kg per 100 litres. (600 litres total)

In order to remove the wastes from 1kg fish 0.6 is given to us as the amount of planted area required to clean the wastes.

So, in this instance 1m2 fish pond requires 14.4m2 planted area. (0.6 x 24)

225mm diameter towers in 700 x 700 bays provide 1.3m2 planted area from only 0.49 sq metres groundspace.

Knowing we need 14.4m2 planted area to cover 1m2 pond we simply divide the planted area of a tower (1.3m2) into the total area required. We get 11.07 towers.

11.07 towers equate to 5.535m2 groundspace.

So, in this instance, 1m2 pond requires 5.535 m2 groundspace.

Adding in paths, utilising double rows, towers above fish areas (taking no extra room for fish) with paths inbetween, we lose even more ground.

A third of it.

In this example 1m2 pond will need 8.3m2 groundspace in order to be operable as an Aquaponic system.

I think that regulatory authorities need to clamp down on effluent issues, this would force people to become more responsible with things like their fish wastes and their hydroponic wastes, soon aquaponics would take off. And the more people that are experimenting, the more efficient methods that can be found.....

For now though, I guess it is up to people like us.

Yes. And we're doing swimmingly well!

As there are fish that produce more waste via the protein ratio and feed habits, so there are plants that feed far more heavily than others.

In the first six months of production herbs and greens are produced in the above ratios as the system is not yet performing optimally. Once the biological system is 'matured' growth rates increase considerably.

At this stage the introduction of heavier feeders can begin. Tomatoes, Peppers, Cucumbers, Brassicas etc. This will increase the system capacity for waste removal as fish density increases ultimately reaching a peak growth stage when it's time to begin culling larger fish for sale.

In the above example post a groundspace ratio of 1:8.3 is given. I think concentrated heavy cropping could reduce this by 30%.

Planting and fish are both then kept on a continuous cropping rotation providing both system stability and 2 regular income streams.

Aquaculture as it stands, well, the maths is not right. Fishing the oceans to feed farmed fish????

Where's the sustainability in that. Pollution is one thing, no fish left to feed the fish farms is another future reality of the route Aquaculture has taken.

Systems raising veg to feed herbivores/omnivores to feed carnivores is the way of the future in Aquaculture. Both salt and freshwater.