Why My AQUAPONICS Didn't Work OFF-GRID - Homesteading and Alternati...

Will This Work For Your Homestead?

Our system in a nutshell

Four years ago we went through some considerable expense to build a 20x40 greenhouse that would contain a very large aquaponics system. The fish tank capacity was 1000 gallons divided into 4 different tanks. Each tank serviced its own set of grow beds made of barrel halves.

Each of the 4 fish tanks had its own pump system that was powered by 1000 watts worth of solar panels.

How does Aquaponics Work?

Aquaponics and how it works is actually very simple. Fish live and grown in a tank where daily they contribute their body waste. The water from that fish tank is pumped out every hour and flows over a set of grow beds where plants are growing. The grow beds full of helpful bacteria are constantly breaking down the fish waste into usuable nitrates and nitrites that can be absorbed and used by the plants growing in the beds. What you end up with is a perfect ecosystem of fish supporting plant growth and bacteria filtering out water that in turn returns clean back to the fish tank. It works wonderfully.

We ran our system for 3 years with the best growth happening in year 2 and 3. It takes a full year for the bacteria in the grow beds to get established and so it's slow going at first. But you can still grow lots of leafy greens as they don't require a lot of dense nutrients like other plants do that grow heavy produce.

Year 2 and 3 saw fantastic results at growing sweet corn, loads of delicious peppers, tomatoes, cucumbers, spinach varieties, peas, onions and lots more. We were very impressed with how the system was working out.

Growing The Fish

Aquaponics has the added benefit of growing fish. Most people in warmer climates or with climate controlled facilities will usually choose Tilapia simply because you get the quickest bang for your buck. A tilapia fish will grow into an adult sized fish in as little as 10 months with a regulated high protein diet. This was our first hurdle we had to overcome.

Because we are off grid, we could not keep the tanks warm enough, long enough to keep tilapia alive. We are technically in the south of North American but not south enough. Temperatures will sometimes drop below 0 degrees Fahrenheit and -17 Celsius during the winter months. It's not often but it does happen. Tilapia will die when the water temperatures reach below 59 degrees Fahrenheit or 15 degrees Celsius.

So instead of Tilapia, we chose to grow hybrid bluegill fish. Hybrid bluegill are a natural cross between a bluegill and a sunfish. The result is a very large fish but it takes about 2 years to reach the large size you will want to harvest.

Why It Didn't Work Off Grid

The biggest issue was that the water consumption was too great. When the system is at peak performance, you basically have 1000 gallons of water in the fish tanks. And you have another 150 gallons spread out in the flood tanks or grow beds at any given time.

When the temperatures in the green house reach 90 degrees Fahrenheit or above, the water evaporation becomes so great that you basically are losing an average of about 250 gallons of water each week. Now that many not sound like a lot of water but when you remember that our water sources are two ground wells that will run low in the peak of summer, that then becomes a big problem.

An on-grid operation will not have a problem and can refill the water being lost. But for us, it meant to have to transfer about 250 gallons of water each week in summer to top off the fish tanks and keep the system running. Many times our wells cannot handle that kind of water transfer on a weekly basis and support the homestead water needs in other areas.

The Fish Problem

The other issue was the fish and this can simply be tossed up to the learning curve. At first we over stocked our tanks with 75 bluegill in each tank. This was way too many. As they grew, each fish and its oxygen consumption began to grow as well and pretty soon, there was not enough oxygen to support the fish population even with air stones working in the tank. They were getting by ok and then one night a mouse chewed thru the plastic air hose that goes out to the tanks and by morning, we had a massive fish die off on our hands. So we had to start again. The solution, don't overload your fish tanks.

What Will We Do Now?

The plan is to remove 3 of the 4 grow bed sections and fish tanks. We will keep one in operation next year to sprout seeds to be transplanted. But the rest of the greenhouse will be used to grow fig trees starting next spring.

Conclusion

Don't get me wrong. Aquaponics works! It works amazingly well, however it's better suited for an on grid situation that has plenty of access to water in case of evaporation. It also has a lot of fail points. Meaning that if any one thing fails, you could have a disaster on your hands if you don't catch it in time. So I would consider it high-medium maintenance. It requires your daily attention. Checking on your system once or twice a day is fine but you need to keep an eye on it nonetheless.