Choosing a container is one of the most important steps of building an aquaponic garden. Fish tanks, grow beds, and plumbing are the skeleton of your system—the structure without which the living organisms cannot properly function. From aquariums to barrels and even bath tubs, in this guide, you’ll learn the pros and cons of various container options from which you can construct your aquaponic garden.
A popular, low-cost option many early aquaponic gardeners have used is the 55-gallon plastic barrel. These barrels come in four standard colors: white, blue, green, and black. Black is often used for chemicals that are not food safe, so you rarely see black barrels used in aquaponic systems. However, a barrel is not toxic just because it is black. White barrels may not block light sufficiently to prevent algae growth, and you may need to paint them on the outside. Most aquaponic gardeners who use barrels use blue barrels.
In order to use 55-gallon barrels for your system, you’ll need to cut them. These barrels are thick, so you would need a jigsaw or other power saw to cut them. Grow beds are usually created by cutting the barrels in half lengthwise. Fish tanks can be created by cutting out the end containing the bungholes, leaving the sturdy ring in place to provide structural integrity.
Once you’ve cut the barrel, you may find the plastic begins to sag and deform. It is common to support the base of the barrel with boards. You can also screw the cut edge to something (like the half-barrel next to it) to prevent sagging.
Most plastic will break down over time if it is exposed to sunlight. These barrels are thick enough that you’d probably get several years of life out of them, but you may still want to either paint or cover the barrels to shield them from ultraviolet rays.
The intermediate bulk container (IBC) is the big brother of the 55-gallon drum. These are very large containers, so you’ll probably need a truck to transport an IBC from point of purchase to your intended garden site.
IBCs are rounded plastic cubes in metal cages and can hold 275 gallons or more. Like 55-gallon drums, they are designed to hold liquids and usually come with a spigot at the base of the metal cage. As with the 55-gallon barrels, you’ll want to make sure the previous contents of the IBC can’t have left a toxic residue.
The metal cages surrounding the plastic cubes are designed so that IBCs full of liquid can be lifted with forklifts and stacked on top of one another. And even though the metal cages are designed to sustain most of the load, the plastic tank itself has impressively thick walls.
You’ll need some serious tools to convert an IBC into a fish tank. At the very least you’ll need a hole saw and jigsaw to cut a panel out of the top of the plastic IBC cube. For those wanting to lop off the top foot or more (to reuse the top as either a sump or grow bed), you’ll also need an angle grinder to cut the metal cage as well as the jigsaw to cut around the plastic cube.
As with the 55-gallon barrels, cover or paint your IBC system to prevent ultraviolet damage. The fish tank you’ll get by using an IBC tote can be pretty tall—as high as 48 inches in some cases. Some gardeners even fill whole IBC totes with gravel and use them as grow beds.
Aquariums are designed to house fish. But they are designed to display fish with the assumption that you will use a traditional aquarium filter. Aquariums are often kept clear by adding chemicals.
Your plants will filter water, but that water will be full of nutrients. When you combine a clear aquarium with light, water, and abundant nitrate, you will get algae. Algae can use up the oxygen your fish and plants need.
You should also think about whether your fish will be comfortable in an aquarium. If you’re raising koi or goldfish, they’ve been bred to be on display and don’t mind light. But if you’re raising food fish, they have evolved to be shy of light and overhead predators. A clear aquarium will make them feel exposed and vulnerable. You can make food fish more comfortable by giving them hiding places such as sections of large-diameter polyvinyl chloride (PVC) pipe or flowerpots placed on their sides.
Stock tanks are designed to feed, water, and wash livestock. If you decide to use stock tanks in your system, use the sturdy plastic tanks instead of either the galvanized metal tanks or the flimsy plastic tanks.
Stock tanks have several benefits:
The 50-gallon stock tanks are usually about 12 inches high, which is the recommended depth for an aquaponic grow bed. The larger sizes are all about two feet tall, which is a comfortable working height. The rounded shape of the tanks means the water can circulate without the dead spots you can get in a rectangular tank.
If you are able to invest a bit more money and have the space, you can consider fiberglass or plastic tanks that are specifically designed for aquaculture and aquaponics. These tanks are designed to hold 1,000 gallons or more and can be outfitted with windows that let you view your fish.
The downside to tanks specifically designed for aquaculture and aquaponics is they do not have a large customer base. Therefore the components will tend to be a bit pricey and shipping costs, where applicable, can be as significant. Complete systems tend to start around $2,000, not including shipping and handling. On the other hand, these specialty tanks are designed for the job, which can be reassuring. And if you can get these products delivered to a business address, your shipping costs can be drastically lower than residential delivery.
Used bathtubs are an interesting option that you can consider for your fish tank, sump, or grow bed. They are definitely designed to be watertight and can be inexpensive or even free.
A bathtub usually holds only 80 gallons of water, so a bathtub system will not be as stable as one that holds the recommended 250 gallons. Most used bathtubs are built in, so they aren’t designed to look lovely on their own—but a bathtub system definitely sends a message about reuse and sustainability. And with a bit of trim and ingenuity, you may be able to transform a bathtub-based system into a striking design element.
Enough people use bathtubs for their aquaponic systems that several aquaponics businesses have created kits specifically for converting bathtubs into aquaponic grow beds.
Now that you know your container options, it’s time to start putting together the systems for your aquaponic garden! For more information on aquaponic gardening, check out our Quick Guides Aquaponic Gardening: How to Build a Simple Koi Pond and Aquaponic Gardening: How to Keep a Winter Garden Warm. Happy gardening!
From The Complete Idiot’s Guide to Aquaponic Gardening by Meg Stout