It has been cycling for a few weeks as we tested the bell siphons and allowed the gravel growing medium to become clean.
All the materials we were able to purchased in Nicaragua at local stores, except for the pump, which we found.Our hope is to learn how to build, start, and maintain these simple systems so that we can eventually put them in rural communities to help the rural poor to supplement their diets with vegetables and fish protein.
The two barrels are 55-60 gallon tanks. The lower tank is a water storage tank we were given for free. After patching up the numerous holes it had, we decided to use it for the fish tank. The upper tank is nothing more than a 55 gallon plastic barrel cut lengthwise to create two clam shell halves. They are filled with screened 3/4" minus gravel, anything smaller that about 3/8" has been removed before placing in the grow bed so as not to plug the siphon system.
The base of the system is 12 cinder blocks stacked 4 high with a 2"x2" frame to support the grow beds. Each grow bed has a Bell siphon made of 3/4" and 1" PVC components. The design is from Affnans Aquaponics and works great. The advantage of the Bell siphon over that of some other systems is that there is no need for a third barrel. This is important as we are attempting to build the entire system for under $100 and in Nicaragua, used 55 gallon barrels cost $25-30 each.
After setting up the system and cycling for a few weeks, we recently added fish to the system. A friend from Granada, Nicaragua helped me to acquire a bakers dozen of fish (13), 9 Tilapia and 4 tropical lake bass known as Guapote. We placed them in the lower barrel. Within a day we had lost two fish, one of each species. The purpose for the blend of fish is that Tilapia supposedly reproduce rapidly and are vegetarians. They wont eat their young. The Guapote are meat eaters and will help control the population should the female Tilapias reproduce. One of the Tilapias that we have is pregnant. She will be separated from the main tank soon because we want some of those babies for our next system.
Our fish took a few days to adapt to the tank. I have been measuring pH, Nitrites, and Nitrate every other day. Unfortunately I have not been able to test for ammonia because the kit I bought in the States to bring to Nicaragua was missing some test bottles. The supplier is sending me a new kit and friends will bring it down in two weeks. After 5 days of no Nitrite levels, today they were high, which means the bacteria to convert to Nitrates will begin to grow soon. Still no Nitrate levels present.Since we have no plants in the grow beds and the system has not balanced, I have been replacing 15-20% of the the water daily with fresh water that sits out for 24 hours so any chlorine can evaporate away. This should help manage the ammonia levels somewhat and keep the fish from shock. Plants will go in soon.
When we picked up the fish, we got them from a fish farm that produces Tilapia for export to Japan. The fish were in large ponds that were probably 6 yards across by 2o yards long. There were 6 of these ponds and they were filled with thousands of Tilapia fish. What caught my attention was that the ponds were basically stagnant. No water movement, green algae, no aeration. It seemed inhospitable for the fish. Yet they were prospering. I had heard that Tilapia were a hardy species. The farm was feeding them a ground feed used for pig farming. There were two smaller ponds that were used for raising Guapote to add to the Tilapia ponds for population control.
The fish to the left was one of the survivors. I took him out of the aquaponics fish tank because he was twice the size of the others and was bullying the other fish. Just say no to bullying :-)So he is in a separate tank on an extended timeout. Besides, he is about 10" and is just a little shy of small plate size. Mmmm.
I have him in a larger 1/2 barrel tank now and he is doing fine. As I replace the 20% of the aquaponics water, I drain off 20% into the barrel tank of this big fish, and I drain off an equal amount to go towards watering plants in soil.
Ill do my best to keep this part of this blog updated as we get new information and learn new things about aquaponics. Ive learned a ton from different sources, but actually building and operating is certainly raising some questions that I didnt find learn from other websites.
Many thanks to Travis Hughleys Barrelponics and Affnan Aquaponics blog for sharing openly about their aquaponics systems.
Update 24 July 2011:
We added a small NFT pipe to the flood and drain grow beds. We want to see if this can work in conjuction with the F&D.
The tube above the grow beds is our small NFT addition. It is a 4" pipe with 5 holes sized to hold small yogurt cups. The inlet is a piece of garden hose. The outlet a 1/2" pipe draining into one of the flood and drain grow beds. Its a very simple design we hope will function well.
We sized the holes in the tube to accept small yogurt cups. The cups are perforated with a dremel tool. Each cup has about 50 1/8" holes. They sit in the 4" tube. The water level of the tube allows the bottem 1/2" of each pot to be submerged in the water.We are attempting to grow lettuce, arugala, chives, and parsley in the NFT. This is an experiment.
Heres a better view of the planters before setting in the tubing.
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