diy aquaponics

We recently spoke to Gina Gallinetti of MyAquaponics about the aquaponics gardening trend that is becoming quite popular all over the world. Essentially the combination of aquaculture and hydroponics, it's one of the most water-wise ways to grow plants these days. Ideal for large and small spaces alike, you might want to consider setting up your own aquaponics system at home. You don't need much room to construct a tank, which could over time become a fresh food source for you and your family. Gina advises us on how to build one ourselves... You will need:

  • 1 x 300 litre fiberglass fish tank
  • 1 x 180 litre grow bed (for plants, fruit and herbs)
  • 100 litres of hydroball (LECA) and stone crush grow media mix (60 Hydroball, 40% Stone Crush)
  • 1400 litre/hour submersible pump
  • 1 x bell-siphon (stand pipe, 25mm uniseal, bell and protective housing)
  • 1 x aquaponic water-feed system
  • 1 x power fail switch (optional, but recommended in SA)
  • 1 x 12 V DC backup pump connected to 12V DC battery
  • Fish
  • Water
  • Plants (Herbs/Vegetables/Fruit Plants)
Tools required:
  • 1 x side cutters
  • Hacksaw or pipe cutters
  • 30mm hole saw and drilling machine
  • Level
  • If the system is outside, we recommend protective housing for any electrical points and plugs.
Step 1:
  • Find a flat and level surface in your garden or backyard for your fish tank and grow bed. A concrete or paved area would be best, but not necessary. Even an unused patio will do.
  • Ensure there is adequate lighting for the plants you will be growing (at least six hours of sunlight per day). If your system is covered by a patio, you can use a grow light to help growth (LED grow lights are recommended). If additional lighting is needed, you can fit a grow light to your patio ceiling.
Step 2:
  • Once you have your fish tank and grow bed secured on a level surface, you can start fitting the pump and the aquaponic water feed system. (An aquaponic water feed system moves water to both the grow bed and back into the fish tank; this system is great for aquaponics as it provides the fish tank with a splash on the surface, giving essential oxygen to the fish. This system can also be adjusted by the valves, allowing for a lesser or greater flow of water which is needed when you need to balance the flow of water into the grow bed).
  • Important: Don’t add any water until you have fitted your pump.
  • Place your 1400 litre/hour water pump at the bottom of the fish tank (but don’t secure it, as at a later stage you might need to move/clean it, which can get a little difficult when the fish tank is filled with water and fish).
  • Connect your aquaponic water feed system to the pump.
Step 3:
  • Drill a hole in your grow bed for the bell-siphon. To do this, use a 30mm drill hole-saw and drill a hole 25cm from the side of the grow bed, just off the centre line.
  • Clean any excess fibre-glass out that might have fallen into the fish tank below or any in the grow bed.
  • Push the bottom of the uniseal through the hole on the planter box and insert the stand pipe through the box.
Step 4:
  • Fit the rest of the bell-siphon onto the stand pipe.
Step 5:
  • For a backup system (optional): Place the 12V DC backup pump in the fish tank.
  • Connect a 1m long aquarium pipe with a 20mm outer diameter to the pump outlet. At the other end of the hose add a 90’ joint, then a 5cm length of hose followed by another 90’ joint to move water into the planter box.
  • Connect the backup pump to the 12v DC battery. You can connect an optional power fail auto-switch to turn on the backup pump in the event of a mains power fail. Once all is connected, test your backup system by switching off the mains power. If connected properly, the backup system will run.
Step 6:
  • Ensure both the grow bed and fish tank are clean and no toxic waste are present. Never clean your fish tank and grow bed with any chemicals. Any chemical is dangerous for fish and can damage their gills, resulting in fatalities.
  • Fill with water, turn your pump on and plant. The best water to use is borehole water. Otherwise, to ensure all chlorine is gone from your system, fill with municipal water and let the system run for 48 hours before adding plants and fish.
Step 7:
  • Fill the planter with your grow medium of choice. Turn on the system and adjust the flood and drain system (bell-siphon) lavel to around 20-30mm below the growing medium.
  • Wet your grow medium to prepare for planting.
Step 8:
  • Carefully plant your seedlings of choice. (Don’t plant mint in an aquaponics system, as the roots of mint tend to take over!)
  • What plants to use: You can plant any wet root-loving plants. However, tomatoes, cucumbers, lettuce, celery, basil and strawberries thrive in this environment. Experimenting with different plants can be fun as well as rewarding!
Step 9:
  • You can put many types of fresh water fish in the tank. Take into consideration the climate of your area. For example, tilapia do well in aquaponics systems, however they must be kept at water temperatures above 22’C.
  • Otherwise, catfish, carp or trout also do well. You can even keep ornamental fish such as koi and goldfish. Make sure you comply with any regulations on keeping certain fish in your area.
  • Don’t forget you still need to feed your fish – the only additive over and above topping up your system with water.
Safety note:
  • Add a net or heavy cover to the open side of the fish tank to prevent children and pets from falling in.
  • Make sure all electrical points are well insulated.
  • Have fun and enjoy growing your own food in your own backyard!
For more information visit, email or call 011-465-8579.