What You Will Need to Building Your Small Aquaponics System

Small Aquaponics System

Before we get on to the subject of what goes in your aquaponics system, instead of buying a complete kit from the shop, I thought I would tell you how to make your own. This is just a mini aquaponics system but once you have the hang of building small, you can easily enlarge it. Starting small is also the perfect way to see exactly how an aquaponics system works and how the nitrification cycle works in an aquatic environment that is constantly recirculating.

What You Will Need

The following list is what you will need to building your small aquaponics system, most of which you can pick up at your local pet store and hardware stores.

  • A fish tank – between 3 and 20 gallons, depending on how small you want to start. You can also use a large glass or plastic container instead if you prefer
  • 2 ½ lbs. gravel for every 5 gallons of water in the tank
  • 3-4 watt water pump, able to lift water at between 18 and 54” at between 30 to 100 gallons per hour. A small fountain pump is ideal
  • Plastic tubing to fit onto the water pump outlet – about three ft.
  • Aquarium air pump – make sure you get the right size for the amount of water in your tank
  • 1-3” air stone
  • Air tubing that fits the air pump and connects to the air stone – 3 ft.
  • Growing medium – use pea gravel, perlite, expanded clay pebbles, coconut coir or peat moss – enough to fill up your grow bed
  • pH testing kit – if necessary, either pH up or pH down as well
  • Fish and plants – more about those later on
Tools Required
  • Electric drill with a ¼ or 3/16” bit and ½” bit
  • Electrical tape
  • Scissors
What the Components do
The Fish Tank

This doesn’t have to be glass, it can be made of Plexiglas, or you can use any other clean plastic or glass container that holds enough water without leaking. It must be between 3 and 20 gallons although if you have the space and want to, you can go larger if you like. If you want to start small, go for a plastic amphibian cage from your local pet store. They hold around 3 gallons of water and are not expensive. That said, standard 10 to 20-gallon fish tanks are not expensive either and, the larger you go with your tank, the larger the grow bed your system can support. A general rule of thumb is that 10 gallons of fish water will support a grow bed of 1-2 square feet.


This is for the base of the fish tank and it will be the home for the nitrifying bacteria – these convert the ammonia from the fish to nitrite and then on to nitrate that is used by the plants in your grow bed. Most pet stores stock gravel, either standard or colored. Make sure to get gravel that is about 1/8” in size and wash it thoroughly before you place it into your tank. If you don’t, you will cloud up the water and clog it up with dust and dirt from the gravel.

Water Pump and Tube

The water pump is required to pump the water in your fish tank into the grow bed, after which it will be fed by gravity back to the fish tank. You must use enough tubing to run from the water pump outlet up to the top of the grow bed and to form a circle inside the grow bed.

Air Pump, Air Stone, and Tube

It is not just the fish that need air; your plants do too, and the air pump should be able to pump sufficient air for both systems. A piece of the tube connects the air pump and air stone together (the stone should be at the bottom of the tank). The air stone works to break up the bubble stream that comes from the pump into much smaller bubbles, which then work to oxygenate the water.

Grow Bed

The grow bed must be sited on top of the fish tank, and it should be a little larger, both in width and length, than the tank. The grow bed will have growing medium in it for the plants. Any container that fits the size requirements will do the job so long as it is between 3 and 8” deep. If you want to, you can build your own from Plexiglass so long as it is sealed with silicone glue that is not toxic. If you do it this way, you can incorporate your aquarium light into it by making a cavity that it will slide into. If you use a ready-made container, the light can be placed behind it.

Growing Medium

The growing medium must be a porous material, one that I chemically inert, to hold the roots of the plants and hold in moisture. You can use expanded clay pebbles, perlite, peat moss, coconut coir, pea gravel, etc., so long as you have enough to fill up the grow bed.

Fish and Plant Life

The way an aquaponics system works is that the fish in your tank provide the nutrients that the plants in your grow bed need; the plants will consume those nutrients, purifying the water in the tank at the same time.

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