Basics of Aquaponics: 5 Key Elements of an Aquaponics System

 

There are 5 key elements of an aquaponics system. Each of these are necessary to run a successful aquaponics system. We'll go over each of these elements in detail below.

The 5 Key Elements of an Aquaponics System:

  1. Grow Bed
  2. Fish Tank
  3. Fish
  4. Plants
  5. Bacteria

 

Grow Beds

In aquaponics, selection of appropriate grow beds for plants is critical. Because plants are the “money maker” for most aquaponics systems, this is one of the most important choices for a grower.

  • Media Beds and Containers: Long-duration crops do best in media such as rocks or expanded clay balls. With media-filled grow beds, aquaponics systems can grow tomato plants and even trees.
  • Deep Water Culture (DWC): In DWC beds, the roots of the crops are bathed in deep pools of water inches deep. This ensures plant roots have access to water and nutrients in case of power outage. Deep water retains temperature, crucial for plants out of season, such as lettuce in high summer. DWC beds typically produce 20% more quantity per plant than the NFT beds favored in hydroponics.
  • Nutrient Film Technique (NFT): In NFT, plant roots obtain water and nutrients from water flowing through the bottom of a tray. NFT grow beds are light, but if the water flow stops, the plants will die. Water flow could stop because of clogging or loss of electricity. NFT systems are less productive than DWC on a plant by plant basis, but denser crop production can make NFT the better choice.

 

Fish

Though fish are usually not the “moneymaker,” proper selection of fish is critical.

Most common fish types found in aquaponics systems:

  1. Tilapia
  2. Goldfish
  3. Koi
  4. Catfish
  5. Bluegill
  6. Jade Perch

Key things to consider when selecting the fish for your system:

  • Are the fish domesticated? Only some fish do well in tanks.
  • What crops are to be grown? Fish should feed well at the same temperature at which the plants thrive.
  • Are there facilities for dealing with sick fish?
  • Are the fish harvested, or are the fish permanent residents of the system.
  • If the fish are to be harvested, how is this done?  

 

Fish Tanks

Proper selection of fish tanks is critical to system design. Some key considerations are:

  • Tanks that suit the fish. Tanks must be large enough for the species selected. Rectangular tanks are rarely appropriate, primarily because they allow solid wastes to collect and rot in corners.
  • Proper tank drainage. Tanks should ideally have a central drain in the bottom of the tank or a configuration that allows solid waste to easily get out of the tank. Mechanical removal of wastes is at least tedious and at worst produces “poop slurry,” which will be difficult to handle.
  • Attractive, durable tanks that are pH-neutral. There are numerous tank options, and few of these options are incorrect.

 

Plants

Picking plants for your system is the fun part. There are many different plants that you can grow in an aquaponics system but the most common is lettuce. Usually you want to grow plants that are compact, grow on vine, or remain relatively small. This is because larger plants can be difficult to support from falling over.

The most common plant types found in aquaponics systems are:

  1. Lettuce
  2. Tomatoes
  3. Peppers
  4. Basil
  5. Cucumbers

Don’t limit your imagination to just these plant types though. You can grow almost any plant variety in an aquaponics system.

 

Bacteria

There are two types of bacteria in aquaponics systems: beneficial bacteria and pathogens.

Beneficial Bacteria

Beneficial bacteria transform animal waste into plant nutrients. These are the engine that makes aquaponics work.

Fish produce ammonia as a by-product of living. The majority of this ammonia goes directly into the water through the fishes’ gills. The simple presence of this ammonia attracts the nitrifying bacteria that like to “eat” ammonia and eventually transform it into the nitrate plants need.

A mature aquaponics system is a richly biotic environment, producing lush growth. But a new system may need to cycle for weeks before the nitrifying bacteria are robust.

Pathogenic Bacteria

Fish rarely harbor human pathogens. But aquaponics is not immune to food-borne illness. Backyard gardens and small farms don’t typically produce enough food to require regular testing.

Best practices are:

  • Keep animals other than fish (dogs, cats, rodents, birds) away from your system.
  • Learn how to keep your fish healthy and follow those measures.
  • Wash food before eating. 

 

Summary

Understanding each of the elements of aquaponics is key to running a thriving aquaponics system. From fish selection to grow bed selection, it is important to think about your objectives and constraints before building your system. Click here to learn more about the benefits of aquaponics. Click here to learn about how to get started with aquaponics.

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