This is a special guest post from Brian Filipowich, Director of Anacostia Aquaponics. To keep getting great content from guests like him, make sure you check out our vertical farming newsletter.
Aquaponics epitomizes the beauty of the closed loop production model, but it’s a little hard to get into. Here, Brian walks you through the easiest way to get up and running with decent yields from a DIY aquaponics system for your living room.
The Easiest Aquaponics System for Beginners
Aquaponic systems come in a dramatic range of sizes and configurations, from multi-acre industrial facilities to table top fish bowls that grow one sprig of parsley. But the most basic system is a media grow bed stacked on top of a fish tank, as pictured below.
*[editors note – I included links where you can purchase all the materials Brian mentions if you want to get started quick and cheap. I also made notes in parentheses on a few along the way. They are affiliate links – feel free to use them or not, but it’s an easy way to help support all the free content on this blog if you’re going to buy the products anyways.]
The system pictured here is in my living room. On the bottom is a 30-gallon fish tank with a few gold fish. A submersible pump (this is about the gph you want to get your water high enough out of your tank) runs continuously, sending the water up to the media bed filled with expanded clay balls, known as Hydroton (that’s the stuff you need. Stick to name brand. If you just want to check out the material, here’s the smaller sized bag).
I currently grow some mint, basil, green onions, and thyme. A bell siphon drain sends the water back down into the fish tank. I also have an aerator stone (I’ve used this one and it works just fine for this application) for extra oxygenation.
To build this system I first designed a frame to house the fish tank. An important note: water weighs 8 pounds a gallon — make sure your structure can handle the weight! On the top of the structure I built a trough and lined it with a water-proof liner known as Dura – Skrim (that’s all you need for a small project like this). The top trough is removable in case I need to get into the fish tank to conduct maintenance or cleaning.
This stacked media bed system is the easiest aquaponic system for various reasons. [editor’s note: check out another take on an aquaponics table]
Only Two Water-Proof Troughs
This system only requires two water-proof troughs: one fish tank and one media bed. The plumbing is simple, because all you need is one pump to lift the water from the fish tank to the grow bed, and one drain from the grow bed back down to the fish tank. And because the troughs are stacked, this system takes up less space and only needs one support structure. Many aquaponics systems include multiple fish tanks and grow troughs which add more plumbing, more space, and more complication.
The Media Bed Serves as a Solids Filter and a Biofilter
The fact that this system employs a media bed also adds to the simplicity. Media beds are one of the three main hydroponic methods used in aquaponic systems. A media bed is a water-proof trough filled with a media such as clay pellets (pictured here), lava rock, gravel, or any other inert substance capable of supporting plant roots. Alternatively, the deep water culture (DWC) method employs large floating rafts with plant roots hanging into the water below. The nutrient film technique (NFT) has plants supported in long narrow channels with their roots hanging into a thin stream of water.
The picture above is a top-view of my stacked aquaponics system, with the Hydroton serving as the media. Media beds are convenient because the media serves as both a solids filter and a biofilter. The media will hold onto fish solids that get pumped up from the fish tank. Inside the media bed this solid waste will have access to enough oxygen to break down and mineralize, releasing nutrients from the fish waste to the plants. Conversely, DWC and NFT systems require a separate solids filter to address the solid fish waste.
In addition to solids filtration, an aquaponic system also needs a biofilter to house the bacteria that convert the ammonia from the fish into nitrates for the plants. A biofilter is a fancy name for something with a lot of surface area for bacteria to colonize. The pebbles, balls, or stones of a media bed have enough surface area to serve as the biofilter. Conversely, DWC and NFT systems require a separate biofilter. The additional solids filter and biofilter for DWC and NFT systems represent two more pieces of hardware, more space, and more plumbing.
Ebb and Flow Drainage for Aeration
The media bed also makes aeration easier. Aquaponic systems require a minimum amount of dissolved oxygen for the health of the plants, fish, and bacteria. Most media beds increase their oxygenation naturally with an ebb and flow water cycle. Either a timed-water pump or a bell siphon can be used to produce a gradual rise and then near-complete drain of the media bed. As the water ebbs to the bottom of the grow bed, oxygen is brought into the water and directly to the roots of the plants. A DWC or NFT system will require supplemental aeration.
A media bed on top of a fish tank is the most basic setup for an aquaponics system and it has been tried in many forms. For instance, below is pictured another version with a used “IBC tote”. These IBCs are famous in the aquaponics world for enabling this “chop and flip” system. The format here is the same as the system in my living room: fish on the bottom, plants on the top. In both systems, there are only two water-proof troughs, no external solids filter, no external biofilter, minimal aeration, minimal plumbing, and a self-contained unit with minimal area.
In contrast to the simple stacked media bed system, pictured below is a large commercial aquaponics system from Lucky Clay’s Fresh in North Carolina. This system has multiple fish tanks, multiple DWC grow troughs, multiple filters of different types, advanced plumbing, and advanced aeration. Of course, this system can pump out a lot of veggies and edible tilapia. But before you’re ready for a big system like this, start with a basic design!
Brian Filipowich owns and operates Anacostia Aquaponics, an aquaponics service provider and think tank in Washington, DC. Brian is also the Director of Public Policy for the Aquaponics Association. A big player in innovative farming in DC – I can’t wait to pick his brain on How Vertical Farming Would Work In DC. In a previous life Brian worked on Capitol Hill for the Senate Banking Committee from 2007 to 2015.