An aquaponic system can be as small as an aquarium with a small grow bed attached up to a fish tank holding thousands of gallons of water. No matter what the size, there are several items you will need.

Fish tank
You will need a container large enough to provide a comfortable space for your fish to grow. The rule of thumb is 1 pound of fish to 2 gallons of water in the fish tank. The tank should be made of a substance that will not leach any chemicals into the water. Commonly used items include:

• aquarium
• IBC (Industrial bulk container)
• stock tanks

Grow beds
The grow beds can be any container that is approximately 12" deep and will hold water. The size of the grow bed will depend on your space available and how you can access it. A typical system will support up to 2 gallons (volume) of grow bed area to 1 gallon of water in the fish tank. Commonly used items include:

• barrels cut in half
• stock tanks

Grow media
The grow media is what the plants will grow in. This is also where the bacteria that make the system possible live. The goal is to find a media that is will hold up over a long period of time, that has a good surface for the bacteria to grow on and that is functional for working in while caring for plants. The best size is around 1/4 - 1/3". Commonly used media include:

• hydroton
• pea gravel

Other items:

• perlite - the challenge with perlite is that it does break down over time and will then end up throughout the system rather than limited to the grow beds. It also has a tendency to float

Water
The fish and plants will need a good source of water. The beauty of the system is that once it is setup and running, very little water is typically needed except to top off as water evaporates. If you will be using city water, you will need to determine what the city uses for disinfection. If only chlorine, the water can circulate in the system for a few days without fish and the chlorine will dissipate. If chloramine is used, you will have to get a special chemical from a pond or aquarium shop to remove the chloramine from the water.

The best source of water is rain water assuming you have a safe surface to collect it from. We used water from a metal roof and also from an asphalt shingle roof. Our particular shingles do not have any zinc or copper added to inhibit moss so we felt it was safe enough.

Plants
In my reading on aquaponics, it appears you can grow just about anything you have room for. Some plants will do better in a more mature system while others will grow great from the start. Starting with leafy vegetables and herbs seems to be common and then advancing to more demanding plants like tomatoes, peppers, etc. Personally, I've always had the idea that gardening was a grand experiment so will be growing a selection of all my favorites from the start. I am also going to include my citrus trees that are currently in pots in the system.

Fish
Aquaponic systems are desigend for freshwater fish. Many people grow their favorite locally available fish such as perch, blue gill and trout. Another great fish is tilapia. In talking with other people who have aquaponics systems, they indicate the fish taste very good and have a great texture in their own systems. Some store-bought tilapia can have an off flavor that is not present in aquaponics grown tilapia. Tilapia grow at a fast rate and are prolific breeders. Each state has different regulations in regards to the fish you can grow and any limitations. You should contact your state fish and wildlife department to determine what will work in your area.

Tilapia Resources:

• SRAC Fact Sheets on Tilapia
• /www.worldfishcenter.org/Pubs/GIFTmanual/pdf/GIFTmanual-04.pdf">Breeding and Rearing of Tilapia

Bacteria
The invisible key to the functioning of an aquaponics system is the bacteria. The fish in your system will produce ammonia and fish waste. In addition, there will be left over bits of food that do not get eaten. All of this is what will eventually become the nutrients for the plants. The ammonia is converted to nitrites by bacteria called nitrosomonas and then nitribacters convert the nitrites to nitrates. This is called the nitrogen cycle. The plants can then utilize the nitrates as food for growth. As the system matures, othe bacteria will continue to break down the other wastes in the system to help provide all of the nutrients the plants need.

You can read more about the nitrogen cycle at University of Florida, IFAS Extension