Before you start building your own DIY aquaponics system in your backyard or even buy an aquaponics kit, it is IMPORTANT that you have a good overview and understanding of the basic components of the aquaponics systems and their respective functions.
In this post, I will be sharing with you the basic components of a media-filled bed aquaponics system, as it is probably the simplest and most reliable aquaponics design for any beginner to start with.
I will also reveal the place where you can find easy to follow step-by-step instructions to build your very first aquaponics garden, with no prior experience.
Basic components of a re-circulating media-filled bed aquaponics system
The main components include the fish tank, plant grow bed and a re-circulation path for the water. The nutrient-rich water has to be pumped from the fish tank to the grow bed for the plants to absorb and remove excessive bio-nutrients. The clean water is then returned to the fish tank, typically via gravity.
While it is possible for some plants to be grown directly in the fish tank, it is recommended to keep the fish tank and grow bed separate to allow for greater flexibility.
Bacteria are required to convert the toxic ammonia-rich waste, nitriles and the suspended solid waste into nitrates and dissolved solids, which only then can be absorbed and utilized by the plants. These bacteria are naturally occurring in the water and surface of fish tanks.
However, in an aquaponics system, the fish population is denser so more bacteria would be needed!
Hence, in aquaponics we need to introduce something known as the bio-filter, which provides addition surface area for the beneficial bacterial to cling onto and live in. There are a variety of bio-filters available, including upright or horizontal bio-filters.
Tip #1: Most backyard aquaponics design combine their grow beds and their bio-filters into a single unit, as in the case of a media-filled grow beds. This simplifies the design and construction of their aquaponics systems, as well as saves cost and space!
The media-filled grow bed is where the plants are cultivated. Grow beds can be made of wood and lined with water-proof plastic liners. Depending on where you stay, you might want to consider adding insulation to the sides of your grow beds to keep it warm in the winter and cool in the summer if your aquaponics setup is in the outdoors. The optimal sizing of the grow bed vs the fish tank is crucial to the success of your aquaponics system.
Most commonly used media to fill the grow beds are expanded clay pellets and gravel (smooth river stones). The objective of the media is to provide good root support to the plants and increase the surface area on which the beneficial bacteria cling to and live.
Essentially, the media also acts as a bio-filter! Gravel has been found to be a great habitat for the beneficial bacteria.
Factors to consider when choosing the media:
- Particle size should be 8-16 mm. If the particles are too small, there will be too little air space in between the particles and the flow of water could be obstructed. Remember that the plant roots require oxygen and good water circulation! If the particles are too big, the surface area would be greatly reduced and the plant roots would also not be able to be well-anchored.
- pH of the media should be neutral. Expanded clay and most river stones are pH neutral. However, NEVER assume that all gravel is pH neutral. Some local crushed rocks or gravel may contain limestone or other pH minerals, which are undesirable. So, always check before purchasing.
- Gravel is much heavier, hence you will need to design and build strong supporting stands to withstand the weight. Expanded clay is light but it is considerably more expensive than gravel. Hence, some aquaponics gardeners have chosen to fill the bottom of the grow beds with gravel and the top with clay.
Configurations of media-filled bed aquaponics systems
There are two different configurations of recirculating water between the fish tanks and media-filled grow beds:
- flood and drain (also known as ebb and flow)
- continuously flooded
TIP #2: Personally I would recommend the flood and drain aquaponics configuration.
The flood and drain configuration has been tested and proven to provide good and even distribution of the incoming nutrient-rich water throughout the grow bed. The periodic flooding and draining of the aquaponics system also increases aeration to the media as well as the water returning to the fish tanks.
Hence, it helps to increase the oxygen supply to the fish, plant roots and bacteria living in the media-filled bed.
Tip #3: Gravel is typically used in the flood and drain aquaponics systems. Expanded clay is usually preferred for the continuous flow configuration as the expanded clay can absorb and retain water to keep the roots wet.
The fish tank is probably the largest and heaviest component in your aquaponics system. As it will be too difficult to be moved around once it is filled, it is important to first carefully consider its location.
Your choice of fish tank will also depend largely on your goal of aquaponics. Are you building a small aquarium-sized system for decorative purpose? If yes, then you will be restricted to growing small aquarium fish.
However, if you are intending to rear ‘plate-size’ fish for food, the fish tank should be large and sturdy enough to hold at least 50 gallons of water. The fish tank should also be made of materials that are food-safe materials.
For example, animal stock tanks made of USDA approved polyethylene with UV inhibitors. Alternatively, you can also construct your own fish tanks from just about any structures or recycled materials, lined with EPDM pond liners.
Next step: Find out more…
Hopefully you have found the above tips and information to be useful. However, these tips alone will not be sufficient to get your DIY aquaponics system built.
What I suggest you to do now is check out Aquaponics 4 You, the #1 selling DIY aquaponics guide.
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