Backyard Aquaponics
A place to discuss aquaponics

As promised here is an update on the all in one rabbit hutch/growbed/wormery. The piping is done and the duck weed and azolla are growing fast. The water quality has improved by leaps and bounds and the rabbits are happily situated in the shade. The koi fish love to eat the fresh duck weed and azolla. I have read that people in some parts of Asia even eat duck weed as it is higher in protein content than an equal mass of soybeans. The duck weed and azolla can even be used as a green fertilizer, not only containing trace minerals, but also tons of nitrogen. Mosquito fish and pond snails also live up above the rabbits. Such a nice little ecosystem we have got here. We are getting closer to closing the loop in our food chain. What do you guys think?

Duck weed!

Here is a close up of the stand pipe which allows for nice water flow without letting the duck weed escape.

Nutrient, calcium carbonate, water, and sunlight... all that cyanobacteria need to thrive. The quest for spirulina has begun and we are off to a great start. Im guessing the shrimp are gonna love this stuff. Solar powered pump circulates water from low to high, and a siphon bridge brings the flow back. From this little design experiment I have found that one can circulate water to any number of tanks with this method, as atmospheric pressure does the bulk of the work to bring the system back into equilibrium. As long as all tanks are at the same height with just a small drop in height for the sump this method can be used to expand existing systems without the need for more pumping capacity.

I am in no way affiliated with Local Roots Aquaponics but I am a fan. Local aquaponic entrepreneur Stephane Herbert-Fort is getting headlines! Great article on aquaponics in Tucson. The article is titled: Tucson, AZ Aquaponics Startup Keeps it Local, Grows Fish and Produce in the Desert. And can be found here---> http://seedstock.com/2013/02/25/tucson-az-aquaponics-startup-keeps-it-local-grows-fish-and-produce-in-the-desert/ Good work Stephane, and best of luck to you.

As a Newbie, I'm interested in designs others have come up with. The buried fish tank intrigues me and I would be curious if you've compared your fish tank water temperature with the ambient outside air temp.

Hello Daneff, thanks for the inquiry. I have compared the submerged fish tank's water temperature with the ambient outside air temp and It is amazing how much they can differ. In the dry Sonoran Desert the daily temperature can swing dramatically. It is the common occurrence for the air temperature to change from 100 degrees Fahrenheit during the day to 60 degrees Fahrenheit at night (38-15 degrees Celsius), that is the forecast for the entire next week starting monday. The fish tank however will stay at a temperature hovering around 74 degrees Fahrenheit (23 degrees Celsius) only swinging a few degrees as opposed to the large temperature variance of the open air. It helps that the tank is both submerged and covered from direct noon and afternoon heating.

During the winter months, I noticed that even on the coldest nights and days when all other water around the house was frozen solid, the aquaponics system was still churning over. I had a five gallon bucket of water on my covered porch freeze solid for two weeks while the fish tank water temperature averaged 58 degrees Fahrenheit. Never did the water get too cold, even in the coldest portion of winter here from late December to mid January. During that time I slowed the feeding rate down to almost nothing. Because of the nature of the hardy fish species I am raising, the ornamental variety of Cyprinus carpio, aka koi / nishikigoi, I do not use a heater during cold months. The only heater being the earths mass and the placement of the opening to the fish tank which allows direct penetration of morning light into the tank. This made a great show as the koi would bask in the morning light. The winter greens were supplemented with liquid seaweed extract and produced just fine without much feed going into the system.

The next system in my back yard will showcase even greater passive solar design. It will feature a large submerged pond 6ft deep with a deck to support an 8ft diameter stock tank. The deck, placed just above the pond on the north west side, will completely shade the water from all afternoon summer sun and allow for direct winter sunlight throughout the day. We are almost done digging the extremely deep hole through extremely hard caliche (calcium carbonate precipitate). We plan to have the system running by July, stay tuned...