DIY Aquaponics System – 20 Gallon Aquarium Conversion

DIY Aquaponics System: Converting a 20 gallon aquarium into an aquaponics system.

This is my first attempt at a DIY Aquaponics System step-by-step explanation, so please bare with me if it isn’t explained as well as it could be.  I would really appreciate any and all feedback on how to make it more succinct, explain the process better, if any part didn’t make sense or if I totally missed something, so I can improve my subsequent DIY Aquaponics tutorials.

Materials You Will Need:

  1. 20 gallon glass aquarium
  2. Water pump
  3. Aerator
  4. Aquarium light
  5. Grow light
  6. Expanded clay pebbles
  7. Plastic seedling tray
  8. Tubing for aerator and water pump
  9. Aquarium gravel
  10. Seedlings
  11. Fish
  12. Aquatic plants
  13. Fish food
  14. Water tester
  15. Wood
DIY Aquaponics Components

DIY Aquaponics Components

Expanded Clay Pebbles

Expanded Clay Pebbles

Building Process

Step 1:  Build the Aquarium Cover

  • Cut a piece of plywood so it fits onto the top of the aquarium.  It should rest on the edges that protrude inward and are depressed about a half inch below the very top of the aquarium.
  • Cut two openings in the back left and right corners of the cover to allow the chords from the pump and heater to exit the aquarium.  These holes will also allow the water that is pumped into the grow bed to drain back into the aquarium so make sure they are large enough for the water to flow back through the cover without contacting it.
  • Cut an opening in the front center of the cover so you can feed the fish.
DIY Aquaponics: Aquarium Cover

DIY Aquaponics: Aquarium Cover

  • Drill a hole in the aquarium cover to allow the tubing from the aerator to pass through it and enter the aquarium.
  • Coat the cover with a sealant so it doesn’t rot.  You can use aquarium grade silicone to seal it.
DIY Aquaponics: Aerator Tubing Entrance

DIY Aquaponics: Aerator Tubing Entrance

Step 2:  Build the Grow Bed

  • Build a box to contain the plastic seedling tray (for aesthetics).
  • Coat all wood with a sealant (aquarium grade silicone works) so the wood wont rot if contacted by water.
  • Drill holes in the back corners of the box and seedling tray to allow the water to drain back into the aquarium.
DIY Aquaponics: Grow Bed Drainage Hole

DIY Aquaponics: Grow Bed Drainage Hole

  • Place the finished seedling tray into the wooden box.
DIY Aquaponics: Grow Bed

DIY Aquaponics: Grow Bed


Step 3: Build the Frame.

  •  Use 1/2 inch dowels and 2×4’s to build the frame for this aquaponics system.  (anything that achieves the same purpose can also be used)
  • Build a base that surrounds the bottom of the aquarium.  It will rest on the same thing that the aquarium rests on.  Cut the 2×4’s into blocks about 2″X2″ for the four corners of the base.  Then drill holes into the blocks so that will allow the insertion of the dowels into these holes to connect the base of the frame.  Make sure the dowels fit into these holes tightly so the frame doesn’t fall apart.
  • Cut the 2X4 into two pieces that are 4′ tall.  Next, drill a hole through the bottom of the 2X4 at a height that the dowel that connects the base of the frame together can slide all the way through the 2X4 attaching it to the base (make sure the 2X4 rests on the same surface the base does so it is stable).  Then, drill pairs of holes through both 2X4’s starting 6 inches above the fish tank’s top and ending an inch bellow the top of the 2X4’s at 4-6 inch intervals.  The sets of drill holes at the top of the 2X4’s allows the 2X4’s to be connected to one another by two dowels, thus securing and completing the frame.
  • The drill holes bellow the top holes that connect the frame will be used to attach the light and allow it to move up and down vertically, so you can adjust to the height of your growing plants!
DIY Aquaponics Frame

DIY Aquaponics Frame


Putting It Together

Step 1: Setup aerator.

  •  Pull the tubing from the aerator through the drill hole in the aquarium cover.
  • Attach the end of the tubing to an air stone.  Do not put the air stone in the tank or the cover on yet, leave it to the side.
DIY Aquaponics: Aerator Setup

DIY Aquaponics: Aerator Setup

Step 2: Fill tank with gravel and environment enhancers.

  •  Fill the bottom of the aquarium with substrate, gravel and any other environment enhancers you wish to use.

Step 3: Setup the pump and the aquarium heater.

  • Attach enough 1/4 inch tubing to the water pump to allow the tubing to reach the grow bed.
  • Attach the pump to the left side of the aquarium with its suction cups.

Step 4: Fill tank with water and (optional – plant aquatic plants ).

  •  Place a plate on the gravel or whatever you put on the bottom of your tank so that when you fill it with water it doesn’t move.
  • Fill the tank up with water and plant whatever aquatic plants you wish to have in you’re aquaponics system.

Step 5: Put the aquarium lid on and run chords and tubing through the holes in the cover and out of the aquarium.

  • Place the air stone that is attached to the aerator at the bottom of the aquarium.
  • Pull the chords and tubing from the heater and water pump the the back corners of the aquarium where the holes in the cover are so that the cover can be placed on top of the aquarium.

Step 6: Setup frame around the aquarium.

  •  Put the frame together and make sure it is secure.
DIY Aquaponics Frame

Step 7: Thoroughly clean expanded clay pebbles by running clean water over them until the water running off of the pebbles is completely clean and clear.

Cleaning Expanded Clay Pebbles

Cleaning Expanded Clay Pebbles

Step 8: Fill the grow bed with the cleaned pebbles.

Step 9: Clean all dirt off the seedlings’ roots.

Cleaning Seedling's Roots

Cleaning Seedling’s Roots

Step 10: Plant the seedlings in the grow bed making sure the roots are all the way under the expanded clay pebbles.

Step 11: Place the grow bed on top of the aquarium cover.

DIY Aquaponics

DIY Aquaponics

Step 12: Attach water pump tubing so the outflow is going into the grow bed.

DIY Aquaponics: Attaching the Water Pump

DIY Aquaponics: Attaching the Water Pump

Step 13: Attach the grow light to the frame at an appropriate height above the seedlings.

DIY Aquaponics: Attaching the Grow Light

DIY Aquaponics: Attaching the Grow Light

Step 14: Run the water pump and aerator for a couple weeks to establish bacterial colonies that will filter the toxins out of the water for the fish.

Step 15: Add fish to the aquarium after the bacterial colonies are properly established.

DIY Aquaponics: The Finished Aquaponics System

DIY Aquaponics: The Finished Aquaponics System

I hope this helped, thank you for reading.

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