Fish tank aquaponics

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Project: Fish tank aquaponics.

Decided to tranform my 4ft goldfish tank to grow vegetables, powered by nutrients provided by the goldfishes. There are currently only 5 small goldfishes and some cories. I reckon the goldfishes will grow bigger and provide more waste in the future, so not adding anymore livestocks.
Current setup has already been running for few years, so it is actually a simple modification, using the backup overhead filter and pump to tranport aquarium water to the plants.

Some consideration includes:
Lighting
Growth bed
Pump and pipings
Height of plants
Nutrient to plants
Additional waste coming into fish tank.

Lighting:
I tied my 4 tubes T5 lights to the top of the aquarium stand, to provide growing light to the plants.
A timer will switch on the lights daily at 1pm, and switch them off at 8pm. I think I will start with 2 tubes first, and monitor the results.


Growth bed:
I will be using a stackable overhead filter as the growth bed.
Went over to my trusty aquarium supplier, Yishun618 That Aquarium shop, and got my supplies. As a member, I get some discounts.
Here's what I got.
A stackable OHF base ($20)

3 Stacks OHF tray ($4 each)

My existing net pots. Each tray can fit 8 net pots, so I can grow 24 pots of vegetables at any one time.


Pump and pipings:
I will be using my existing eheim 101 pump which can deliver 600 litre of water per hour.
Bought a Y tube ($2.5), and 6 rainbars ($3.5 each) and 6 connectors ($0.5 each).
The Y tube and 2 sets of rainbars will provide water to 2 rows of net pots.


I assembled the rainbars, and using some existing rubber tubes I have to connect the Y joints and rainbar, and to my existing L bar that connects to my eheim pump.

Next, I use my soldering iron to cut some curve on the tray, so that the rainbar can sit nicely. Using black tape to secure the rainbar in place.

Moment of truth: the pump is turned on. Everything works like it should. No leakage, which is an aquarist's nightmare. Noise level from dripping water from the rainbar is quite acceptable.




Height of plants:
I will be growing short plants, as height between the light and growth bed is only 15cm tall.
Nai bai and weeks old spinach will be prime candidates.

Nutrients to plants:
Mostly nitrogenous waste from fishes. I will not be supplementing iron or potassium or phosphorus, because I am growing leafy vegetables and harvesting them in weeks. But if they fail the taste test, then I might add more fish safe fertiliser.

Additional waste coming into fish tank.
I will adding additional white wool to act as mechanical filter. Not too concern about biofilter for the fishes, as there is one existing 4ft established OHF filter in place.