Saturday, October 27, 2012

Passive Lettuce Farm

I'd like you to imagine a wall of 1 gallon plastic milk jugs set at about 45 degrees so that the tops of the jugs protrude from the cavity in the wall.  In the spout there would be a paper towel shaped into a cone and filled with some small grow media like Coir.

In the jug there is a volume of nutrient rich water from your aquaponic system.  When first planted from seed each container would have one lettuce plant inside the cone of media.  The level of the nutrient rich water would be just high enough at first to moisten the cone.

As the lettuce grows the solution would be used and the level would fall creating an aerobic space where some of the roots become exposed.  As the plant contiues to grow the solution will be used up by the rrots that grow into the water.  5 to 7 weeks later the lettuce is mature and ready for harvest.

Several weeks create a harvest that required no electricity for pumps!

Here is an experiment I started a few days ago.  The water is slowly being used as the plants grow

For more information on this technique CLICK HERE

Compare this to a high production commercial hydroponic system

Thursday, October 25, 2012


I have been plagued with Pythium when starting new seeds and this information presented by Nick Savidov may just help me and find the cure.

This is a very good scientific study of aquaponics,  I highly recommend looking at it.

The Perfect System

Originally I posted this to show the tank arraignment, but then added temperature control, green house design, and lighting.  I feel these are the best ways to design an aquaponics system.

But aquaponics may not be the best way to grow food.   Fish are, as Vlad put it, "a romantic attraction", but most will agree that it complicates the process.  Raising fish does not provide fish at a lower cost than current retail grocery store prices, and conditions such as temperature, and pH in the vegetable garden are often comprised

Peeponics, or Bioponics require no food, or comprises, and allows you to concentrate your efforts on growing vegetables.  Without fish poo to clog up the system, the plant roots will remain clean and healthy.  Without the overhead of fish food the cost of your vegetables will be lower.  Plants require less temperature control.  The list goes on.  We produce urine every day - sadly it's a wasted resource.

I highly recommend reading this PDF about Aquaponic design.  It is without a doubt one of the best papers I've ever read.  I wish I had followed the advice presented from the beginning.  But the school of hard knocks is often required before we come around to a full understanding of the gems available to us .

Like I said  'Optimization of Backyard Aquaponics for Food Production'.  is one of the best documents I've read.   I read that paper carefully taking note of the calculations involved, and created a spreadsheet to help with the design of a system.

The spreadsheet is available at

What follows below is the best of everything I've learned.  Apply it to either Bioponics,or Aquaponics.   

The Perfect Back Yard  System combines the Sump and Raft

Here is a link to

Murray visits the USA teaching Commercial Aquaponics

Tanks & Pumps

This system can be sized up as shown here.  But if you are a beginning aquapon I suggest starting small with a system like the one Murray is standing next to.  The independent media beds allow maintenance on one while the others remain undisturbed.  The large sump tank prevents radical water level changes and the grow beds placed at the same level as the sump simply circulate water through a series of rafts returning water back to the sump.  Only a very small 30 GPH pump is required because there is no head pressure.  30 GPH is extremely low flow, but this has proven to be all that is required, even in very large rafts.  Click this link for a very interesting video!   To use an airlift pump the sump tank would have to be deeper than shown here.  Airlift pumps appeal to me because they aerate while moving water and blowers are far more reliable then water pumps.


A geyser pump, an improved airlift pump
An Airlift Pump Spreadsheet is available at airlift_basic_calculation.xls
Multiple fish tanks allow you to raise generations separately and cull the runts from each generation.

There are no filters to clean,  Passing the water through the media beds cleans the water coming from the fish tank.  Vermiculture is used to keep the media clean.  Using a Timed Flood and Drain system will save utility costs and avoid the problems associated with bell siphons.

Enlarging the system as shown here would require two pumps but one will be used intermittently to pump water from the sump to the fish tanks.  The other will be a very small pump which will be very inexpensive to run.   

Overall this system satisfies all the requirements of a reliable, low maintenance,  and low energy system.  Periodically the drip holes would need to be cleaned, and of course water tests and feeding.  But that's about all there is once the system is established.  

The drip holes are not located on the stand pipe as you might imagine, but rather on a 1" pipe connected through the side near the bottom of the media bed.  This allows for easy access and periodic cleaning.  It also places it where you can see the weep holes, and be aware of any developing problems.  Using a Uniseal at this connection also allows the pipe to be removed easily if deeper maintenance is required.

An Aquaponic Valve is a mechanical indexing valve... there are no electrical components.  While this could be used to sequence the Flood & Drain of each media bed to further prevent water fluctuations in the sump, and raft tanks, this is not required due to the total volume of the sump and raft tanks. 
Here's another DIY Indexing Value built and designed by Rob Torcellini

There has been some research with aerobic rafts the called GW Raft system.  I would like to incorporate a simpler version of that by placing boards with net pot holes over the top edge of each raft.  The water can be adjusted by the length of the stand pipe.

The height of the water could be adjusted higher with the stand pipe to allow the net pot to wick.  As the roots grow the level can then be adjusted lowed to provide the air space.

To gain even better flow with the air pump I have designed this system 

...Download this Sketchup Model..

This system has two radial filters and a media bed to keep the deep water culture raft very clean, An air pump keeps the water moving via an air compressor; no mechanical pumps are required. Water levels in all the tanks are the same. By not raising the water from a sump tank only a small amount of energy is required.
This is how my system is set up.  Everything in one tank.  Pots are placed on the platform suspended just below the water and wick the moisture up.  The fish swim underneath.
I currently use a 6" airlift pump to circulate the water in the fish tank, but I'm working on adding a 45" deep tube through the bottom, so that I can get a real good flow.  I'll post pictures when that is finished.

Garden Enclosure

One additional note about making this perfect is the need for a green house.  An efficient green house can be built if insulted well on three sides and glazed on the south.  My experiments have shown that the Summer temperatures will not get too hot.   Enclosed growing spaces require ample air exchange.  Mold and insects can become a major problem over night. I highly suggest making a option to open the enclosure.

Temperature Control


My research into Rocket Mass Stoves has lead me to believe Winter heating can be accomplished without added utility.

Solar is also an option.  This system was built and documented by Paul at Gardening Rhythms.


Supplemental lighting will be required in the Winter only because of the short days.  But Ceramic Metal Halide can provide efficient full spectrum lighting at a reasonable cost.

Running an aquaponic system may seem simple at first glance.  Feed the fish and grow perfect vegatables.  Don't be fooled by the simple appearance of these systems.  Read "Integrating Fish and Plant Culture" first.  Take note of the complex chemistry described in the section "Nutrient dynamics".  This is one of  the best and most comprehensive articles I've ever found.

Timed Flood and Drain

My pursuit of an energy efficient system continues.   Yesterday after about 6 months of flawless operation my bell siphon failed to drain.   This inspired me to find something simpler, less expensive and more dependable.  I remembered this conversation on AquacultureHub

By simply providing small drain holes at the bottom of the media bed a Hybrid Flood & Drain / Ebb & Flow can be created.   I have long been a proponent of Ebb & Flow due to the energy savings.

Here's how it works:
It's pretty simple.  There's a stand pipe that keeps the water from exceeding a set level about 1-1/2" below the gravel, and a weep hole (about 5/16") that drains the water out.  The pump comes on just a few times per day.  While the pump is filling the grow bed the water seeps out.  But the pump fills the tank much faster than the water leaves, so it fills.  The timer need only be set on long enough for the grow bed to fill.
In the Summer you may need to run the pump more often, but I run mine 3 times per day all year long.  The gravel stays moist and the water is aerated sufficiently for the fish.
By running the pump only a few times per day you save utility costs, and there is no siphon to fail.  I inserted a capped 1" pipe at the bottom of one of my grow beds and drilled my weep hole in it so that I could see it and this makes cleaning the hole very easy.  I can remove the cap to get inside if need be.  I've been running my timed flood and drain for several months and the hole has not clogged, but it does not hurt to inspect it once in a while. 
The timer I use is just a cheap $3.00 indoor timer with a plastic food storage container over it.  I poked a couple holes through the plastic, and plugged the timer in.  It stays nice and dry this way, and  easily accessed by removing the cover of the container.

Here are the conversations between John Burgess, aka RupertofOZ,   Glenn Martinez,  and J. Linden Rose.

System Design Considerations

Comment by J. Linden Rose on August 31, 2012 .
   Many people use gallon of fish tank to gallon of grow bed ratios. This has a minor flaw, because nutrient uptake and removal by plants is directly related solar surface area, and only indirectly related to grow bed volume assuming root development plays a large role in your particular crop. But before you can say something like 3 sq. ft. of grow bed per gallon of fish tank, you need to think about stocking density and feed conversion ratio (FCR).
   In this industry everyone is taught to sell their tilapia when they are no more than a year old. The reasoning is that when fish are small and young, the FCR is smaller, and less feed becomes more fish faster.  That's useful thinking in the aquaculture world, but lacks a certain breadth of consideration in the AP world. You might consider an aquaculture strategy that focuses on growing larger, older fish.  Remember that AP systems produce about $4 of produce for every $1 of fish in a Rakocy style system which has been optimized around fish production.  By lengthening the grow-out period for your fish, the FCR will increase, but it will also stabilize allowing you to have better control over the nutrient stream to the much more important produce side. Additionally, higher FCR means more nutrients end up in the plants than in the fish... which is where the money is. This in turn should imply that larger fish lead to larger grow beds.
   With that in mind, its probably a good idea to see your system as one that will go thru many changes when it is new. Then as your fish mature, and your nutrient stream stabilizes, you will be able to fine tune the grow bed surface area to match.
   Gravel beds, a type of fluidized bed reactor, are the oldest and most established form of modern aquaponics, and were first used in the work of Woods Hole researcher John Todd at his New Alchemy Institute, and Dr. Mark McMurtry at NC State.
   Dr. Jim Rakocy, a RAS (Recirculating Aquaculture Systems) aquaculture specialist at the University of the Virgin Islands in St. Croix, abandoned gravel beds because he wanted to work around the issue of sludge build-up. To avoid sludge issues, he developed raft culture, which in the absence of a bed reactor, required settling and degassing tanks. This system falls short of optimal for several reasons: 1) you're spending money on nutrients your plants need that you then remove from the system wasting resources 2) his floating rafts blocks most of the air-water interface for gas exchange intensifying the need to waste electrify on compensatory aeration, and 3) this system design is fish-centric, obsessed with how many fish you can cram into a barrel, when Jim's own publications showed that the aquaculture side was a minor contributor to revenues, and 4) only a very limited number of plants can tolerate having their roots immersed in water 24/7.  Typically plants with low nutrient requirements and low ability to scrub nutrients from the water.
   Tom Speraneo, is credited with the first use of tilapia in AP systems, but also is credited with cycling the water level in the gravel beds, creating enormous amounts of temporary thin water surfaces for gas exchange, and facilitating aerobic RAS waste processing. But the other interesting development was that it made the beds capable of sustaining active vermiculture, which further breaks down and decomposes the solid wastes, and restores lost nutrients instead of wastefully removing them.  This seems to have been confirmed by the systems popularized in Australia by Joel Malcolm and Murray Hullam, with Murray claiming to have systems that have run without any waste removal being necessary for over 3 years.  Similar results have occurred in Hawaii with Glenn Martinez's system.
   Using the archaic meaning of vermiculated of "worm eaten", we can call these vermiculated fluidized bed reactors, and their use should free up a great deal more nutrient from the same amount of feed input, allowing you to focus on the much more profitable produce production side of an AP system.
   With that in mind, Wilson Lennard has shown that raft cultures seem to be slightly more productive with low nutrient crops like lettuce, whereas most crops cannot be grown in rafts at all.  Since lettuce has a very fast seed to crop cycle, it can provide stead cash flow while waiting for more valuable crops to mature in the gravel beds, and with all the extra nutrients available, there's plenty of reason to have both in your system design.  This will also increase the total system volume, which is good for fish, and if you design your deep water wells with tops that are not floating on the water, you'll have greatly enhanced gas exchange surfaces.
   It would probably be a good idea to avoid NFT (Nutrient Film Technique) completely if your system includes fish production, because a thin layer of water spread out over long distances is basically a heat exchanger, which will cause diurnal temperature swings in your fish tank greatly adding to their stress levels.
Comment by Glenn Martinez on September 1, 2012
   First, most of us have fallen into a trap of running our aquaponic (AP) systems 24 hours a day. Think again....perhaps it should be shut down at night, drain the bio-filter (cinder beds) and let the system rest at night. Keep pumping the AIR to the fish, but stop running the water thru the vii-filter and float beds. This saves energy. It also allows the fish water to build up ammonia that will then be sent the bio-filter beds. Very quickly the bio-filter will convert the ammonia to nitrates.
   As long as you do not let the ammonia build up in the fish tank, you are okay. It is recommended drain the bio-filter bed when it is not circulating, as leaving water stilling in the bio-filter, seems to deplete the oxygen (everything is composting) and kills the worms and oxygen loving bacteria....
   The worms in our AP systems (cinder beds) eat the fish solids, breaking them down. Most important to keep in mind that our siphon system is NOT inside the bio-filter, but removed and located in an container that will drain the vii-filter "drip dry" at each flush. All of our bio-filter beds are "double tray" or false bottom, to allow drip dry draining. The drained bio-filter bed will NOT dry out over night and the plants do not suffer.
   To drain the bio-filter beds at night, place a small hole in the stand pipe of the bell siphon or install a small drain tube to drain the bio-filter bed when the water stops coming in for any reason , like a power failure.
For balanced nutrition, add vermicast or compost tea. That will supply all the micro and macro nutrients you need to grow NUTRITIOUS food, kala etc.
Food for thought.
Glenn, Olomana Gardens, Hawaii
Comment by John Burgess on October 17, 2012

   "To drain the bio-filter beds at night, place a small hole in the stand pipe of the bell siphon or install a small drain tube to drain the bio-filter bed when the water stops coming in for any reason , like a power failure."
Just run a standard overflow standpipe... and timer... flood & drain configuration... ditch the siphons altogether...
   Part of such a configuration... is the (generally) two small (6mm) holes at the base of the standpipe.. to allow the grow bed to "drain" during the timer off period...
   And utilising a timer based F&D... means it's simple as... to turn the beds off or limit/extend the F&D cycles.. during the night... or as a response to climatic variables...

Wednesday, October 24, 2012

Regenerative Blower

I bought a Hydrofarm ActiveAqua 70 lpm air pump at the beginning of June.  About a week ago it started to make a self destructive noise that became unbearable. 
In a pinch for air I bought an EcoPlus 7 air pump.

  I like this new EcoAir pump. 
 EcoPlus Commercial Air 7 - 200 Watts - outputs 200 liters/minute @ 5.1 PSI -  It will pump as deep as 141”  1/2" ID TUBING
EcoPlus Commercial Air 5 -   80 Watts - outputs 80 liters/minute @ 4.2 PSI    -  It will pump as deep as 116”
EcoPlus Commercial Air 3 -   35 Watts - outputs 65 liters/minute @ 3.9 PSI    - It will pump as deep as 107”
These run much cooler and slightly less noisy,  but I've been on the hunt for a good deal on a Regenerative Blower and today won an e-Bay bid for an Ametek Rotron EG DR083.   This is an ultra quiet 18.4 cubic feet per minute air blower.  That's equal to 521.03 liters per minute!  It should draw about 100 Watts, but it will push air nearly 24 " deep. 

The Hydrofarm ActiveAqua pushed 70 lpm at zero inches.  This regenerative blower will deliver 70 lpm 20" deep!
My thinking on this is that I may be able to pump water while aerating.  Looks like I'll be getting back into air lifts. 
The main reason I wanted this pump is dependability.  A piston pump seems to me like a self destructive device by it's very nature, and besides that they are loud and annoying.

 This short video contains good information about air pumps, blowers, and distribution systems

Wednesday, October 17, 2012


Yesterday Justin and I visited a catfish farm in Gerber CA.  The owner Don has been raising catfish since 1987 .  When we arrived he was taking Dissolved Oxygen reading of his 16 ponds.   He showed us his operation.  He and his daughter who also raises catfish on her farm sell their product in the bay area.  Don recently attended the aquaponics class in the Virgin Islands and intends to incorporate AP into his aquaculture.

Justin and I are thrilled to have met Don and left with 50 fingerling which we divided.
I places 6 in my warm tank and the rest in my outdoor IBC system.  The little fellers looking happy and are a lot of fun to watch.

Friday, October 12, 2012

DIY Pond Filters

Here is a link to a forum where an under gravel filter is suggested.

This also looks like a good idea to me.  One thing I learned is that at first when my fish were small there was very little debris to deal with, but as the fish reproduced and grew bigger it became a problem.  At one point I was cleaning the filter everyday. 

My feeling is that a large gravel bed with 3/4" rock and vermaculture will require the least amount of maintenance and provide a great amount of bio-filtration.   But sometime the situation calls for a filter and these appear to be pretty good.