Difference Between Hydroponics and Aquaponics Part 3

1. Media Filled Grow Bed

 

Aquaponics Media Filled Bed ContainerAn Aquaponics Media Filled Grow Bed comes in just about all sizes and shapes depending on the system type  in use. In this image, a container of 30 X 24 inches  is typically filled with media to within 2 inches of the top of a 6-12 inch deep container. The pipe on the left is pouring water continuously over the media of Hydroton pebbles that is pumped in from the fish tank.

The Hydroton media is a self-contained biofilter because the surface of the porous pebbles of clay,  provide a home for the bacteria to grow. This in turn becomes the rich nutrients that the plants feed on.

Aquaponics Grow beds of this size range will need to be sturdy enough to hold the weight of pebble media and the water. Holes need to be drilled on the side of the bed and fish tank to accommodate pipes that run water in and out of these containers. Most growers will use PVC fittings, plastic washers, and silicon caulking to properly waterproof the pipe-to-container connections.

This size of grow bed container means more media in the bin which results in more bacteria growth. Since the bacteria converts the ammonia to nitrates that the plants feed on, another  result is more fish that can be added to the aquaponic tank.

Grow beds often need a water pump that trickles water continuously over the media keeping the roots of the plants moist. The size of the Grow Bed container and whether or not it needs a pump, will depend on the type of aquaponics system you choose to build. We will go over some of the more popular types  of systems in this article as well as other posts on this Aquaponics Grow Bed website.

IBC Aquaponics Grow Beds

One type of media grow bed that is often  used is the IBC aquaponics container tote. Typically,  gardeners building an ibc tote aquaponicsaquaponics system, will purchase an IBC tote and convert it into an a media filled grow bed and an aquaponics tank for fish. They do this by first cutting the bars of the outside cage and then the Intermediate Bulk Container itself. This leaves two containers, typically 25% height for the grow bed and the remaining 75% for the aquaponic fish tank.

The top section of the IBC is turned upside down becoming a grow media container for the plants. The larger part serves as the fish container. A submersible pump sends the water into the grow bed through a plumbing system. (usually of PVC). 

 

Aquaponics Systems in Detail

 

2. DIY Deep Water Culture System

backyard pondDeep Water Culture for Aquaponics is also known as Raft or Floating Systems that go back to the history of aquaponics. The Ancient civilizations of Aztecs and Asian cultures grew their vegetables on rafts floating in ponds and swamp-like environments (see image left). It has now developed into hydroponic systems and more recently Aquaponics Systems.

As mentioned in our summary from  Aquaponics Grow Bed, this system is light on maintenance and best for leafy fast growing vegetables with small root systems. The components we use most are for small to medium systems that are suitable for hobbyists and home-based growers, as opposed to commercial systems that require more space and expensive equipment. But both have their benefits and and are capable of wonderful produce harvests.

deep water culture vegetablesDWC layouts resemble other types of aquaponic systems that require routine management to keep plants, fish and the bacteria population in good health. Compared to deep water culture vs ebb and flow, draining water from the grow beds aren’t needed with DWC. Two basic types of systems are in use, both with plenty of modification design hybrids out there.

1. The Float Tank. This uses grow bed areas of Styrofoam insulation rafts that float on top of a tank of fish. Plants grow in net pots that are placed in holes in the Styrofoam allowing the roots to dangle in the water continuously. This simple design can be used indoor and outdoor using tanks, aquariums and even backyard ponds.

2. The Canal System. This is similar to the other but a little bit more complex. The fish tanks are separated from the grow beds that are canal channels or troughs. Some growers use big ibc aquaponics totes that we went over earlier in this article
Each trough or channel has its own deep water culture water level. It’s also different in that submersible pumps are used to deliver water to the grow beds from the fish tanks. It’s a larger system than the Float Tank version and circulates the water more efficiently. It is used successfully by commercial growers and is a promising method for sustainable solutions regarding global food issued. Some growers use the bucket system we went over in  diy deep water culture bucket system, but they seem to require more manual management, particularly with the fish tank component.

A Filter(s) is placed between the fish tank and the grow beds in the larger systems like the Canal Type. Included but not always used are,  swirl filters, nitrafication filters, screens or reverse osmosis filters, and waste solids filters. Be advised that the solids will require manual cleaning weekly.

The fish tank supplies not only the fish, but also their waste that is ultimately converted to nitrates that the plant roots absorb as nutrients. The fish waste excrement becomes ammonia that goes through a conversion to nutrients thanks to colonies of bacteria that live on the surface area of the tank- If you want to learn more about how this process works go to our article Aquaponics Biofilter Essentials

 

Deep Water Culture Tips

The fish tanks should have some sort of device that aerates the water. Airstones with an external pump work well as it creates bubbles of air that helps to increase the oxygen levels.

The systems water needs to be tested routinely to:

1. Be sure the pH is at proper levels

2. Confirm the water temperature is stable

3. Verify that the nitrification procedure is in order

It’s also a good idea to check that pumps are working properly and the tube or pipe network is in good condition. It’s important to clean out any excess material that gets in the filters or blockage may clog the system.

Aquaponics Components Needed for Deep Water Culture Systems

  • Canal or Troughs- Grow beds for holding the plants and water pumped in from the fish tank. Several of these containers can be used depending on how much produce you want to grow.
  • Float or Raft Grow Beds- made of some type of foam for the plants to reside while floating on the fish tank unit. Holes in the raft allow the plant roots to be constantly suspended in the water below.
  • Fish Tank- This is where the fish live as well as the bacteria that acts as a biofilter and converts fish waste to nutrients for that plants.
  • Filters- Several types can be utilized between the grow bed(s) and the fish tank to keep the system efficient clean and healthy.
  • Water Pump- Used in the Canal System to pump water from fish tank, through any filters that are deployed, into the canal channels, and also used to recirculate the water through the system
  • Aeration Device- Airstones with external pump are recommended

3. NFT Aquaponics System (Nutrient Film Technique)

aquaponic garden designThis Aquaponics Grow Bed type is housed in long pipes similar to gutter downspouts you find on buildings. They are usually about 10 feet long and have a narrow channel down the middle where the plants grow.

Some Aquaponics growers use cylindrical PVC pipes 3 to 4 inches in diameter. However,  rectangular shaped pipes are recommended because of increased space for the roots on the flat surface bottom. Vinyl fence posts make a good NFT grow bed. This is used to avoid metal pipes that may rust and contaminate the water.

Like the floating raft grow bed, the NFT system implements constant water flow. The plumbing design pumps water from the fish tank and through the channel where the plants grow, and then back to the the fish tank in a continuous flow.

NFT Aquaponics SystemThe container space is smaller in a NFT Grow Bed therefore a separate bio filter component is needed . This is because the bacteria won’t have enough water and surface area to flourish inside the NFT channels. You can find a bio-filter mechanism online to suit the size of your NFT system. Here is more information about Bio-filters

NFT Grow Beds are used for limited crop types like lettuce and other leafy vegetables. Some smaller veggies that fruit, like strawberries, will also do well.

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