How to Build DWC Aquponics System: Aquaponics DIY Series
There are three main aquaponics methods; the Media Based method, Nutrient Film Technique (NFT) and Deep Water Culture/Floating Raft Systems. Each has it’s own pros and cons, NFT setups are more suitable for vertical farming whilst Media Based systems suit flat grow bed tanks, and DWC systems are suitable for either, but each provide growers with the option to setup in or outdoors, and to precisely control levels within the system so that both plants and fish can thrive comfortably.
In this article we’ll be following a short but comprehensive video series produced by Petani Kota87. The three part series contains all the information you’ll need to build an NFT aquaponics system from scratch, from affordable readily available parts. All info and images are accredited to Petani Kota87, check out their videos for more indepth aquaponics tutorials.
How the NFT Method Works
NFT aquaponics is based upon the Ebb and Flow hydroponics technique that utilizes raised, sloped grow bed channels that allows nutrient-rich water to flow constantly from one end to the other past the roots. Aquaponics modifies this system via the addition of a fish reservoir and a mineralization tank. This creates a closed loop system where the toxic ammonia fish waste can be broken down and converted it into nitrates that can then be recirculated to feed the plants.
NFT aquaponics systems are suitable for beginners, easy to maintain and easy to diagnose problems. They require less water than media based and DWC setups; however, water pumps must remain in use 24/7 to keep the water flowing. They require very little growth medium required, and have nutrient requirements as a result. The setup can be relatively easy to build, especially when using modular, off-the-shelf parts that are designed to fit together.
The NFT method works best with small plants that are quick to harvest and aren’t heavy, since roots grown in small net pots cannot handle the weight of top-heavy plants.
Building Your First NFT Aquaponics Set Up
Once you’ve selected the building site of your NFT aquaponics system, you’ll want to draw up some blueprints. You’ll need to take accurate measurement of the space, and pay special attention to dimensions, as this will be your guidelines during the project so it’s vital these instructions are correct. These plans will double as a checklist and act as your guidelines for the project; therefore it’s crucial that measurements are taken accurately so the build and installation of the system will go without a hitch.
Blueprints will also give you a visual overview of the project, which will help you spot any mistakes, things you may have missed, and/or any areas that could be improved. NFT aquaponics setups are comprised of three main components connected in series to create a closed loop system:
Fish Tank > Grow Bed Channels > Mineralization/Filtration Tank >>> [Filtered Water Recirculated Back To Fish Tank]
It’s a good idea to check out other designs online, this will give you a better idea of what’s possible, what’s within your capabilities, and what will fit your chosen location. You plans don’t need compete with architectural blueprints, but it is a good idea to accurately measure dimensions since the plumbing network must be watertight.
Starting with the fish tank and grow beds, NFT setups present the option to suspend grow bed channels above the fish tank in vertical/stepped configuration. This allows water to fall from the end of the channels directly into the tank; alternatively grow beds can be setup adjacent to the tank, in which case piping can be installed to carry water from the channels to the tank.
Next you’ll need to plan out the plumbing network to connect the mineralization/filtration tank to the grow beds, and the fish tank back to the mineralization tank. You’ll need to install a water pump, or airlift pump, to move water from the mineralization tank to the grow beds. Depending on the configuration of your setup you may also require an air pump and airstone to aerate the water.
Once you’ve got a clear idea of how exactly the build will be done, you’ll need a list of materials and tools. To build the setup we’re looking at today, here’s what required:
- Silicone Tape
- Silicone Waterproof Caulk
- Epoxy or strong adhesive
- Tarpaulin Tape/Vinyl Cement
- Saw/Circular Saw/Table Saw
- Drill (with Forstner bit for drilling larger diameter circles)
- Vice (optional)
- Measuring Tape
- Set Square
- Tarpaulin and PVC piping: for reservoir
- PVC piping and joints/connectors: for grow bed channels and plumbing
- Net Pots/Cups: for plants
- Water Pump or Airlift Pump
- Air Pump and airstone
- Mineralization Tank: Biofilter & Solid Separator
- Pot Nets/Cups
Fish Tank Reservoir
There are numerous ways to construct the main tank; wood is a popular choice, as shown in our DIY DWC article, but since NFT systems do not require as much water volume as deep water culture systems, tanks can be constructed from slightly less sturdy materials such is tarpaulin. Of course you’ll also have the option of using pre-built tanks, purpose built aquariums or repurposed plastic rain water tanks; intermediate bulk containers (IBC) can also be a great solution if you have access to the tools to cut through the metal frame. Depending on your chosen configuration, the tank may require both water inlets and outlets, or may only require an outlet if grows beds are mounted above the water.
Grow Bed Channels
Familiar to some for the common use in hydroponics, NFT grow beds are raised at one end to form a gentle slope to so that gravity can assist the flow of water. This creates a thin “film” of “nutrient” rich water, hence the name; Nutrient Film Technique. DIY NFT grow channels are typically created from PVC piping with holes drilled in the top where plant pot net can be mounted. PVC piping is readily available, affordable, built for the purpose and comes in many modular parts that are easy to put together. The versatility of this building material is, in fact, so useful that it regularly gets used to build tank frames, and other parts of the system that aren’t required to too heavy a load.
Water Pumps / Airlift Circulation Pumps
Water pumps or airlift pumps, are installed to move the water throughout the system. Since the raised grow beds utilize gravity to keep water flowing, most NFT systems typically only use one pump, which moves water from the mineralization tanks to the top of the grow beds. NFT channels mounted above the tanks have the advantage of simply allowing the water to fall and be collected, otherwise further piping installed at the end of the grow beds carries the water onto the next stage of the process; mineralization/filtration.
Unlike other systems, the NFT do not use timers but instead require the water pump to run constantly. For this reason it’s a good idea to use good quality, reliable pumps. Or alternatively look into installing an airlift pump, as they can often be more reliable.
Plumping and Piping
When it comes to installing plumbing, like many aquaponics system, NFT setups often use purpose built PVC plastic piping to create the plumbing network; not only are they cheap they’re also easy to drill and mount net pots for seedlings. Although these work fine, one point to note would be that the more common round pipes make for a base that isn’t flat, and thus may not flow water through the root as efficiently as possible. To avoid this, look for square/rectangle PVC pipe that once lay on the side provide a flat bottom where water can flow more effectively past the roots.
Due to the nature of the design, NFT projects use a lot more PVC piping than other systems. In addition to the plumbing that connects the decoupled components, the piping is also used as the main building material to construct the grow bed channels. Furthermore, DIY fish tanks are also commonly made from PVC piping and tarpaulin (as we’ve outlined in this example), further increasing the amount of piping required, and possibly putting you in a position to purchase bulk amounts at a cheaper rate.
PVC piping offers a variety of different joints and connections so you can build your own custom structure, to your own unique dimensions. The system should be watertight, or at least, should loss as little water as possible. To ensure the plumbing doesn’t leak you run a few cycles to uncover any problem areas, then you can seal up these areas with silicone and waterproof caulk. You can also prevent water leaking from any threaded joints by lining silicone tape around the threads prior to connection.
An alternative, more labor-intensive solution involves routing out channels from wood; in particular bamboo, since it’s hollow and affordable. In addition, advancements in CNC machining, as well as 3d printing and laser cutting have opened doors to a whole world of new construction techniques, so you could get extremely creative if you have access to these machines.
Remember to make sure the whole system is watertight; use running water to help uncover leaks, fix any holes using silicone or caulk, and seal any threaded connections with silicone tape.
Install Mineralization/Filter Tank
Perhaps the most important step of the process, mineralization refers to the two-stage filtration comprising of biofilters, which support colonies of beneficial bacteria responsible for converting ammonia waste from the fish into nitrates for the plants, and solid separators that removes settable solids, suspended solids and floating solids from the water.
One component of the nutrient film technique that requires careful attention is the aquaponics biofilter; the design of NFT systems typically lack enough surface area for the beneficial bacteria and this greatly diminishes the conversion rate of the system and will cause the ecosystem to collapse rapidly. In order to support colonies of bacteria you’ll need to install an additional biofilter. Biofilters contain a filter media such as ceramic noodles, bio balls, or activated carbon, which provide plenty of surface area for the microorganisms to thrive and do their job. You may also want to consider adding an air pump and airstone in the fish tank to aerate the water further and increase levels of dissolved oxygen.
Solid separators are available in several different types, some of these include:
- Swirl Separator/Vortex filter: uses centrifugal force
- Clarifier: Passive system that uses time and gravity to let solids settle to the bottom where it’s then removed
- Radial Flow Filter/Radial Flow Settler (RFS): another passive system that utilizes gravity for efficient particle removal
- Raft Filter: Use a series of meshes to filter out solids
- Bird Netting: Popular for large systems, uses a combination a clarifier and netting
If you were to arrange the difficulty of each stage in this DIY process from the easiest to most challenging; building the mineralization tank complete with effective filtration is right there at the top.
– Choosing to construct your own is a rather complex project; a project we have a tutorial on exactly ‘How to Build Your Own Aquapoincs Mineralization Filtration System’ coming up right here >>>
– If you’d simply like to find out more about aquaponics filters, what types are used, how they work, and how they differ between systems; then check out this article on ‘Aquaponics Filters BioFilters and Solid Separators’ >>>
– If you’re interested in building your own mineralization tank, check out ‘Part 2’ of the ‘DIY : How to make Simple RAS system…’ video series from Petani Kota87. The 8 min clips shows step-by-step how to put together a biofilter and solid separator from affordable, yet durable, parts and materials >>>
With this in mind it’s not surprising the many growers, beginners and experts a like, all choose to use all-in-one solutions that are available to purchase as a complete units from one of a handful of reputable brands.
One of these units that provides the full life support and filtration for the system, is AST Filter’s MDC1000 Aquaponics System. This essentially plug in and play component features both biofiltration and solid separation designed in a single unit for optimal performance. It also includes an automatic backwash mode so the setup self-cleans regularly, which reduces the amount of monitoring and maintenance.
Building your own DIY NFT aquaponics setup is great way to get into aquatic eco farming. Those with experience in hydroponics will find the jump to aquaponics extremely easy, that said, with a little guidance beginners can also have excellent results.
This method of construction will allow you to create an NFT aquaponics setup in any size and configuration you like. Popular configurations for grow channels include the classic appearance comprising rows of flat channel beds, raised channels (sloped at one end to leverage gravity) and stepped or vertically stacked channels. These designs offer fantastic space-saving options, which opens up options when it comes to where you can install the system.
There are many advantages of choosing NFT aquaponics over other methods, and depending on your situation, perhaps a couple of disadvantages too. If you’re still undecided on whether NFT setups are right for you, then check out this Introduction to Aquaponics, as well as our In-Depth Look Into NFT Aquaponics systems.
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