Why in the world would you want to build an aquaponics system?
The following are some of the requests that have come to me for design and development:
- A hobby or herb system.
- A system to supplement my groceries.
- A food system to feed my family.
- A system for income.
- An urban farm system.
- A system for missionary work.
- An educational system to tie in with curriculum.
- A hub system for a larger regenerative or permaculture farm.
There are a few considerations that need to be addressed at the beginning of the planning process.
The number one thing is to know why you want an aquaponics system and the purpose. The answer can’t simply be to grow food. That’s what aquaponics does. The answer to this first question will determine what’s next. For example: Do you buy a system from a company that manufactures them, or do you design and build your own, or do you have a custom design developed and built for you? Is year round growing what you are looking for? Do you live in a climate that it can be operated outside, or will you need a sun room or greenhouse?
Do you have enough knowledge about plants and fish to move ahead and develop a system?
The number one problem that comes back to me after someone has started into aquaponics is immediately after watching the seemingly miraculous growth of all the plants in the system, they begin dying just as fast as they came to life. The number two problem is floating fish in the morning. Number three is, “I can’t get the siphon to work properly.”
Do you have the budget to build/buy a system for your purpose that will include your inputs until the system is balanced?
When the purpose in known, you can do some figuring to know how large your system will need to be and therefor understand what it may cost you to build and operate. If you want to start with a small herb garden or a few tomato plants you can buy a system “off the shelf” from $250 aquarium set up to $5,000. To purchase most of the larger systems manufactured you can expect to pay thousands if not hundreds of thousands dollars.
If your goal is to produce food for sale at markets, to individuals or restaurants, have you done market research? What is the demand in your area? What types of vegetables or greens and at what volume does your prospect need? Have you developed relationships with potential customers? What are they currently paying? This is not “Field of Dreams” where if you build it they will come. Good market research, planning and implementation is imperative for success. When you know the demand you can plan your system accordingly. This is one reason we design modular systems. You can plan ahead for expansion to your system and work with your cash flow to grow your production as you increase your reach and understanding of aquaponics.
If your system is to produce food for your family determining the volume by pounds per person will give you the amount of grow bed space you need. This will help determine the size of your system. Keep in mind that you have to work around the growing cycle based on your climate. If you plan to grow year round and you live in a cool or cold climate you will need to consider heat as an input during cold months. The nice thing is heating water is much more efficient than heating air. The biomass in the grow beds also assists in the efficiency of your heating system.
When it comes to someone who may just be starting out, I usually recommend a small system to start. A great system to get your feet wet is what’s known as BarrelPonics. This was developed by a good friend of mine, Travis Hughey, and you can find free plans here at http://www.fastonline.org/ Plus, there’s quite a bit of information on the site. You can also
purchase another system developed by Travis called MyAqaufarm here www.myaquafarm.com/.
Here’s a couple rules of thumb that may help in determining your system.
Try to keep your grow bed medium at a ratio of 2 parts media to 1 part water by volume in the fish tank. This will help assure you have enough biofilter material for the system. The grow media is housing for the bacteria and microorganisms necessary for the nitrification process to take place. Keep in mind that as the water is being pumped from the tank to the beds the tank level will drop. The media will displace about 2/3 of the volume of the bed. That means that 1/3 of the volume of the bed will be water. That water is no longer in your tank. Your beds (or you have one large bed) will then cycle and that water returns to the tank. You need to plan for this change in tank volume. There are many systems out there that utilize sump tanks that can eliminate the tank fluctuation. We don’t use sump tanks. Our theory is the more simple, the better.
So, here’s the biology. Fish do what fish do in the water. That produces ammonia. If the ammonia builds up, fish die. The water with ammonia is circulated through the system, filling the grow beds. Now what the Creator established begins happening. One set of bacteria consumes the ammonia and excretes nitrites. Too, much nitrite in the system and fish die. So, the second team of bacteria come in to play. They consume the nitrites and excrete nitrates. Too, much nitrates in the system and, you guessed it, fish die. Nitrates are what plants consume, good thing, because that’s what we’re doing here, feeding plants to feed us. The plants consume the nitrates and we have fresh water returning to the tank. I in no way want to insult anyone’s intelligence here, it is a simple thing to grasp and most of us
learned this in middle school. The best approach I have found is to bring people back into remembrance and it kick starts the thought process that will keep us out of harms way down the line.
Learn what you can about vermiculture. We include red wigglers in our systems. These things are amazing! They add nutrients to the system, clean the media up, double in mass every ninety days or so, and make great fish feed. Eventually, when your system balances and you have grown several crops the worms really flourish. Worm bins under the grow beds where you can put table scraps and organic scraps from the system and worms in the grow media can eventually replace quite a bit of fish feed. This is another factor that will reduce your inputs.
In a production system roughly 70% of your space will be taken up by the system. When selecting the space, this needs to be kept in mind. With an educational system the space utilization could be as much as 50% for the system alone. The reason for the additional pace is due to the fact that their will be larger groups of people in the greenhouse at one time.
Depending on the breed of fish you can grow out 1lb of fish per 2 gallons of water. This number is argued all over the internet. I’m talking from experience in a system running at its peak performance, which means in balance. At this point we’re simply looking at capacity for planning purposes. The more fish, the more plants that are necessary and the system needs to be in balance.
You can harvest 2 pounds of food per square foot of grow bed surface three to four times per year. You can get more or less depending on your crops. This information is used for planning so you can calculate how much grow bed surface space you may need. The systems we design/build aren’t simply for lettuce, though we love lettuce. You can grow virtually any vegetables you like in the system. You will realize even more harvest as you grow more vertically. Some vegetables just make sense growing more traditionally due to the fact they can take up a lot of space and if you have space outside and the right climate, it only makes sense. Most of the systems we deal with are part of a farm/garden system that includes garden beds, raised beds and/or wicking beds outside. The aquaponics greenhouse is a fantastic system, but it is not a magic, all-in-all system. At the end of the day, it is agriculture and demands time and knowledge. Keep in mind, the system takes time to come into balance. Usually, the larger the system, the longer time it takes. It can take as many as 6 to 8 months.
The bottom line to begin your plan is considered like this:
- What type of system do I need? What’s the purpose?
- Is there a market for my products?
- What are my production needs?
- How much money do I have to invest?
- How large does my system need to be?
- Do I need to build it all at once or can I slowly expand as I go?
- Will my system be expandable if need be?
- Do I have enough plant and fish knowledge to begin or do I need to take the time to learn more first?
These considerations may seem very basic, and you may be well beyond these, but, for those who are just starting out, this will help you avoid big mistakes and get your plan formalized more easily.
I will be laying out other things to consider in the future. The above few points should give you enough to put pencil to paper. Do a lot of research on the internet to see what type of systems you would be more comfortable with. My advice is to research systems that are centered around grow beds.
I will be explaining the modular systems we design and build in more detail in other articles.