Second Stage Aquaponics
Our second stage aquaponics setup –
Our aquaponics system is pretty low tech. I have a 3200 litre/hour pump in the 60 litre sump that runs into a 60 litre fish tank. Fom there it runs out into 3 grow beds that then drain back into the sump. These beds are of the traditional blue barrel cut lengthwise design and are filled with a mix of 50% clay balls and 50% scoria.
Feed in pipes are 25mm PVC and drain pipes are 40mm PVC.
Branching off of this is a Nutrient Film Technique (NFT) grow bed that consists of 4 PVC channels. This was given to us by our good friend Dave. The water for this is diverted from between the pump and the fish tank so that it can be run independently when the grow beds aren’t being filled.
Above it all are 3 X 36W daylight balanced fluoro tubes and a 36W variable light LED setup. I call it ‘variable light’ because we can play around with the balance of daylight, red and blue LEDs. The lights are only used as supplememtary lighting in the early morning just before sun up and just before sun down and for an hour or so after the sun’s gone.
We don’t want the purple tinged light glowing too brightly or for too long, lest we attract unwanted attention.
The whole lot is temporarily inside of the shonkiest greenhouse imaginable. It is a 3.6 X 1.8 metre shade house frame covered with 3 layers of the cheapest plastic we could find. The whole thing is held together with duct tape and cable ties. It was only made to survive winter and I think it will just about make it!
What plants do we grow?
Year round plants
We have been experimenting with various plants, but the plants we consistently grow in the grow beds are –
These are the plants whose can suffer from the seasonal weather and are best grown at the right time of year, even in an aquaponics system
Beans (assorted varieties)
Pak Choy (Brassica rapa subsp. chinensis)
Spinach (Spinacia oleracea)