How the Aquaponics cycle works

We've all heard of hydroponics, the growing of plants in highly fertilized and treated water without soil. This requires periodic water changes to replace the toxic waste buildups and guess where this usually ends up...

Aquaculture is the culture of fish, trout, perch, etc, in tanks or ponds for restaurant trade or retail. Again this requires massive amounts of energy and water changes to remove the build up of ammonia and guess where this usually ends up...

Both systems need constant attention to water quality to ensure best growth. Aquaponics is the combination of the two, whereby bacteria in the grow beds of clay beads or gravel or even small scoria, develop and change the fish waste (ammonia) into nitrite and and secondary bacteria change this into nitrate which the plants take up for growth. This basically purifies the water that returns to the fish tanks as clean clear water. No need for water changes and once the cycle has established, very little maintenance.

In this system the only feed required is for the livestock, whether fish or crustacean, as adding fertilizers will kill the fish and the bacteria. Pellets for the fish and vegetable scraps for the yabbies is all you need do, every second day in winter and daily during warmer months, and only small amounts so very low costs after initial set up.

Having the grow bed at hip-height also means no bending, there is no weeding or digging and it only requires about 10% of the water used to maintain the average soil veggie patch.

The aim is to produce not only the freshest organic veggies but also fresh fish for the BBQ.

Stage Two

With stage one in full cycle, time to add two more tanks. The total volume of water is approx 600lts with just under 400lts of grow bed area so I still have the opportunity to add more grow beds.
I have connected all three tanks with PVC piping (with crossed wires to stop animal migration) and placed the single pump in the middle that feeds all six grow beds.

I have placed a few yabbies in tank 1 (which I had in pond, now dismantled), and in the warmer spring months will purchase silver perch fingerlings for tank 2. I 'll keep the comets in tank 3 until I have silver perch at two different growth rates, and also as a back up so the system doesn't crash when I harvest the fish and yabbies. Acclimatising the silver perch fingerlings is best done in warmer months - I have no intention of heating the water - I'll get about 12 per tank and six months later buy more to replace the comets. The aquarium shop has offered to buy them back, particularly if they have grown but I've also seen on YouTube Silver perch and goldfish co-existing so will wait on this issue.

Yabbies seem to do better alone, no fishy friends, and I can only keep about 20 in this size tank. Even though I've cut and placed assorted PVC pipes for them, there is a limit due to their aggressive and cannibalistic tendencies, so I am investigating some floating trays/baskets to house more.

Now all I have to do is add the "well rinsed" scoria and let the system cycle. This shouldn't take as long as the first stage as all three tanks are connected and the bacteria is already present in two grow beds.
These new beds will be for spring planting of tomatoes, capsicum, strawberries, broccoli, more lettuce, and if room permits I'll try sweet corn.

Fast growth rate with Home Aquaponics

Now that the bacteria cycle (ammonia to nitrite to nitrate) has established the growth rate is sensational, particularly in the lettuce and celery. The parsley died back to yellow before putting out strong new growth and the chives have only just started coming on.

I covered the return tubing with shadecloth to ensure I didn't accidently drop scoria down there, very hard to get out otherwise. One water inlet at the back was not enough to soak the entire bed, so I made a rectangle of pipe from the water system, drilled opposing holes and now get good coverage over the entire grow bed. Very much a work-in-progress situation.

Putting it all together

Now the fun begins. I stocked the tank with 35 comets (feeder goldfish) to kick start the system. I washed out all the soil from the seedlings and planted celery, chives, lettuce, peas, silverbeet, parsley and at first not much growth. By the 8th or  9th week things really started to improve. I believe it takes about 2 months for the bacteria cycle to get going and I was starting up over winter with less hours of sunlight. The growth rate continues to improve with the celery about 30cm high and the lettuce about the same.

The peas have taken a toll (something ate the whole lot) so another crop has been planted and have started climbing the grid trellis.

It is a simple system, one pump from the tank up to two grow beds. The return water isn't just a hole in the base, its a water trap that only takes from the very base comprising a smaller tube inside a larger one. Water travels up inside the outer tube to overflow over the inner tube which is cut at half height. This was too much water so I drilled holes along the length of the inner tube to regulate the flow - this seems to have worked well. The syphon system seemed too much effort in comparison. 

This system faces north, under the eave so during cold weather it is well protected and in the height of summer will afford some shade to avoid too much evaporation and overheating.

I hope to set up two more systems side-by-side and connect them up to house yabbies and silver perch.

Trip to Bunnings

Bunnings had absolutely everything I needed to create my first setup.
I found a 250lt black rectangular tank, 60lt black tubs, the black gardening watering system for the pump and all the PVC piping anyone could want.
I decided to start with one tank and two grow beds and take it from there. Since I already had a large pump left over from my tropical fish tank, it was easy to configure the tubing to the grow beds and the gravity feed return to the tank using the standard pvc piping. I purchased Scoria instead of gravel or clay balls as I'd read that scoria had trace elements and had a huge surface area where the bacteria would flourish. I also found the grill over the top - being one side of a compost bin cage so in all the first step up, excluding tools I needed like drill bits and hacksaw blades, was about $125.00

Initial Set up of my Aquaponics system

I live in a very heavy clay soil region and drainage is a huge problem for a vegie patch, and space is at a premium with chickens and dogs and kids in a small suburban backyard.
After watching a program on Aquaponics, I knew this was the system for me and my limited space.
There's plenty on the net to read and certainly plenty of setups on offer, the cheapest is about $1k and fairly small, which has a negative impact on growing your own.
Knowing that I wanted the continuous flow version, the set up was actually very easy after some thought and particularly after a trip to Bunnings!