First of all, a little primer on fish tanks. They are an ecosystem creating a nitrogen cycle. The fish eat food and expel nitrogen and feces which decompose and create more nitrogen. There are two types of bacteria that live in a healthy fish tank that convert the nitrogen first to nitrites and then to nitrates. Too much nitrogen or nitrite in the water will kill fish.
The filter in most fish tanks does a little bit of mechanical filtering, but it's primary purpose is to house the bacteria that is essential for the nitrogen cycle. Thus if you thoroughly wash your filter every week because your water is getting cloudy, then you are in a constant wash cycle and are not getting your fish tank where it needs to be for your fish to be healthy.
You can read more here:
http://www.diyaquaponics.info/bacteria.html
http://fins.actwin.com/mirror/begin-cycling.html
http://www.algone.com/articles/aquarium-filtration/nitrogen-cycle
Nitrates are readily absorbed by plants for their nutrient uptake. This is the lynch pin in making aquaponics a self sustaining ecosystem.
I started my aquaponics tanks using clear ammonia and putting some extra operational filters from my indoor fish tanks into the aquaponics tanks (for bacteria transfer).
Sunday, October 28, 2012
Sunday, October 21, 2012
Monitoring Aquaponic Grow Bed Water Levels
With ebb and flow water systems, it is useful to monitor your water level under the surface of your grow media. This is a simple but effective method do that.
As you are filling media into your bed, put a length of 1.5" PVC pipe in the bed vertically in the media. Allow the top to protrude above the media surface by a good 2 inches (5cm) at least. If you are using fine media, it would be good to attach some fiberglass screening with plastic lock ties at the bottom of the pipe.
Now make the indicator using a straw and a piece of styrofoam that is smaller than the diameter of the PVC pipe. Say about 1.5cm in width.
Picture showing styrofoam with straw embedded. Note the graduations marked on the straw. This is long because I use deep grow beds in my setup.
Picture showing the level meter in operation. Water filling the grow bed is causing the indicator to rise.
As you are filling media into your bed, put a length of 1.5" PVC pipe in the bed vertically in the media. Allow the top to protrude above the media surface by a good 2 inches (5cm) at least. If you are using fine media, it would be good to attach some fiberglass screening with plastic lock ties at the bottom of the pipe.
Now make the indicator using a straw and a piece of styrofoam that is smaller than the diameter of the PVC pipe. Say about 1.5cm in width.
Monday, October 15, 2012
Salads with Ebb and Flow? YES!!
In aquaponics systems, salad greens are normally grown in a flow or flood system with the roots continuously in running water. I have a deep bed ebb and flow system and recently populated one bed with mesclun salad mix seed. I used the vermiculite bed for the salad greens. Please see http://wolfenhawke.blogspot.com/2012/10/aquaponics-grow-beds-and-media-stackup.html for various media stackups. Seeds were just spread on top of the fresh vermiculite.
The following picture is a successful yield offered by this method.
The following picture is a successful yield offered by this method.
Sunday, October 7, 2012
Bell Siphoning for Aquaponics Grow Beds
Aquaponics systems use one of two water recirculation systems primarily. One method is the "flood system", "flow system", or "constant flow" system. This system runs the water continuously through the root systems of vegetables. The other method is the "flood and drain" or "ebb and flow" system. This system adds water to grow beds causing the water level to rise to just below the media surface, and then drains the water and repeats the process continuously.
Flow systems are good for salad green farming. Flood and Drain systems are good for all types of vegetables but are a little more complex.
As you have seen from my setup schematic, http://wolfenhawke.blogspot.com/2012/10/single-pump-aquaponics-system-design.html, I use Flood and Drain in my system. This is accomplished by using a bell siphon in the grow bed. This apparatus does not use energy but counts on vacuum created in a sealed water system. There is plenty of information on building your bell siphon. One paper is available here, http://www.ctahr.hawaii.edu/oc/freepubs/pdf/BIO-10.pdf.
Since my grow beds had a drain plug on the side, I used this. I do not recommend going from the side as the setup is more complex to tune, but I am showing this for interest/information. Certainly, you can setup your similar beds with the draining straight down.
As you can see, my internal standpipe makes a 90 degree bend which is non-standard.
After that the bell pipe is installed on the standpipe. Note, one disadvantage with the 90 degree standpipe connection, is that the bell pipe cannot seal as far to the bottom. The top of the cut at the bottom of the bell pipe determines the minimum level of water in the grow bed. My bed will have about two inches of water always at the bottom.
After this stage, you can fill the planter with your media. As you can see, one benefit I do have with the 90 degree install, is that I can tune the height of the water draining by turning the bell pipe and standpipe as a unit. I had to do this on all my planters to get the desired height -- this is likely because I do not use "snorkels" on my bell pipe and the trapped air is compressing and affecting the rising water level.
Flow systems are good for salad green farming. Flood and Drain systems are good for all types of vegetables but are a little more complex.
As you have seen from my setup schematic, http://wolfenhawke.blogspot.com/2012/10/single-pump-aquaponics-system-design.html, I use Flood and Drain in my system. This is accomplished by using a bell siphon in the grow bed. This apparatus does not use energy but counts on vacuum created in a sealed water system. There is plenty of information on building your bell siphon. One paper is available here, http://www.ctahr.hawaii.edu/oc/freepubs/pdf/BIO-10.pdf.
Since my grow beds had a drain plug on the side, I used this. I do not recommend going from the side as the setup is more complex to tune, but I am showing this for interest/information. Certainly, you can setup your similar beds with the draining straight down.
As you can see, my internal standpipe makes a 90 degree bend which is non-standard.
After that the bell pipe is installed on the standpipe. Note, one disadvantage with the 90 degree standpipe connection, is that the bell pipe cannot seal as far to the bottom. The top of the cut at the bottom of the bell pipe determines the minimum level of water in the grow bed. My bed will have about two inches of water always at the bottom.
Saturday, October 6, 2012
Single Pump Aquaponics System Design
I use an architecture in my aquaponics setup that requires a single pump per fish tank used. This minimizes electricity and vastly reduces the complexity of the control system. The water is pumped to my sludge separator design (see blog for details) which is at the highest location in the system. Gravity is then used to move the water from the separator to the grow beds and back to the fish tank. Using more than one fish tank in the same system requires balancing the effluent water from the grow beds and this will be addressed in another article.
The schematic of the setup is shown below:
The fish tank is shown below:
The sludge separator is shown here. The pipe on the right is the influence. The pipe protruding from the front is the overflow back to the fish tank (a safety measure).
Here the piping is shown from the grow beds (3/4") to the collector (2") which returns the cleaned effluent back to the fish tank.
Since I use flood and drain as my water distribution, I could technically just keep the water pump running. I use drains on the side of the grow beds. This side draining is much less efficient than bottom draining and what happens is that the water slows down in draining as it gets to the bottom of the bed. This causes an equilibrium to be reached if the water pump is left on all the time. At equilibrium the water is about 1/3 depth in the grow beds at all times. I alleviate this problem, and save electricity to boot, by putting my water pump on a timer that runs 30minutes on, 30minutes off continuously. This means I only pump half the time. It also allows the grow bed to get flooded and drain once per on/off cycle.
I have not had trouble with the side draining, but it does take a little tuning of the bell siphon. We will cover this siphon design on another article.
The schematic of the setup is shown below:
The fish tank is shown below:
The sludge separator is shown here. The pipe on the right is the influence. The pipe protruding from the front is the overflow back to the fish tank (a safety measure).
Here the piping is shown from the grow beds (3/4") to the collector (2") which returns the cleaned effluent back to the fish tank.
Since I use flood and drain as my water distribution, I could technically just keep the water pump running. I use drains on the side of the grow beds. This side draining is much less efficient than bottom draining and what happens is that the water slows down in draining as it gets to the bottom of the bed. This causes an equilibrium to be reached if the water pump is left on all the time. At equilibrium the water is about 1/3 depth in the grow beds at all times. I alleviate this problem, and save electricity to boot, by putting my water pump on a timer that runs 30minutes on, 30minutes off continuously. This means I only pump half the time. It also allows the grow bed to get flooded and drain once per on/off cycle.
I have not had trouble with the side draining, but it does take a little tuning of the bell siphon. We will cover this siphon design on another article.
Aquaponics Grow Beds and Media Stackup
Aquaponics is the raising of fish (for food) and recirculating the water through grow beds to grow vegetables (for food). The ammonia that increases in the water in the fish tank is converted to nitrite and nitrate through the same process that occurs in a successfully operating fish tank. In a display fish tank, this conversion occurs in the media in your filter and other areas (under the sand). It is important to note that your fish tank filter's primary purpose is providing the media for the nitrogen cycle bacteria to thrive. In aquaponics, this media is the material used to grow the vegetables. The benefit of this is that the vegetation gets the nitrates they require directly as part of reducing the poisons in the fish water. Thus you get a closed nitrogen cycle system.
On the post, Freeland-fp100-as-aquaponics-growbeds I noted the Freeland bins that I use for my deep root grow beds. On this post I will describe the stackup I use for the media. The pictures below show a bed with hydroton as the top layer and one with vermiculite as the top layer.
The beds after being cut are 20" deep. The bottom 6" are washed 3/4" gravel. There is a long air stone buried in the bed at this point. This is optional to have, but I wanted to inject air here to prevent any anaerobic bacterial action here. A summary of the stackups I use is drawn below.
In some beds, I use Hydroton for the whole top layer (about 6" total depth). In some I use about 4" of Hydroton and 4" of vermiculite.
The reason for the vermiculite is for seeding directly and for a variety of grow media depending on plant preferences. Fine seeds work very well directly in the vermiculite. I have had success with mixed salad green seeds, as well as tomato and cee gwa in the vermiculite. I have had success with cee gwa directly in hydroton also. In general for the hydroton beds, I start seeds in coconut husk pots filled with vermiculite.
The vermiculite really encourages robust root growth. When harvesting often the top 3" of vermiculite is saturated with root (especially when growing tomatoe) and this must be disposed of and replaced with fresh material. Below is a photo of vermiculite saturated with tomato root. Also is a photo of cee gwa roots that were grown in hydroton.
Salad growing in a vermiculite bed:
On the post, Freeland-fp100-as-aquaponics-growbeds I noted the Freeland bins that I use for my deep root grow beds. On this post I will describe the stackup I use for the media. The pictures below show a bed with hydroton as the top layer and one with vermiculite as the top layer.
The beds after being cut are 20" deep. The bottom 6" are washed 3/4" gravel. There is a long air stone buried in the bed at this point. This is optional to have, but I wanted to inject air here to prevent any anaerobic bacterial action here. A summary of the stackups I use is drawn below.
In some beds, I use Hydroton for the whole top layer (about 6" total depth). In some I use about 4" of Hydroton and 4" of vermiculite.
The reason for the vermiculite is for seeding directly and for a variety of grow media depending on plant preferences. Fine seeds work very well directly in the vermiculite. I have had success with mixed salad green seeds, as well as tomato and cee gwa in the vermiculite. I have had success with cee gwa directly in hydroton also. In general for the hydroton beds, I start seeds in coconut husk pots filled with vermiculite.
The vermiculite really encourages robust root growth. When harvesting often the top 3" of vermiculite is saturated with root (especially when growing tomatoe) and this must be disposed of and replaced with fresh material. Below is a photo of vermiculite saturated with tomato root. Also is a photo of cee gwa roots that were grown in hydroton.
Salad growing in a vermiculite bed:
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