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Friendly Aquaponics Newsletter
Number 20
September 17th,  2010
Images from our farmily aquaponics farm
Aloha Friend,

We're holding our fifth Commercial Aquaponics Training this October 4-7th in Honokaa, Hawaii. These trainings focus on how to be commercially successful with aquaponics, and in them we share everything we've learned in the last three years of organically-certified commercial operation. Because of our ongoing R&D program (designed to make our operation more productive and economical) we continually add new information to our training materials that will save new aquaponics producers time and money when you set up your aquaponics farm.

We are the first (and currently the only) aquaponics teachers in the world that train people how to get their aquaponics farms organically certified. This is valuable because organic produce is usually worth from 50-100% MORE than conventionally-grown produce. We are also the only commercial aquaponics teachers that actually make their living from operating their aquaponics farm and selling vegetables and fish, rather than selling fish tanks, pumps, and consulting. The others make claims; we KNOW what we're doing.

If you're interested in commercial scale aquaponics, please take a look at our Commercial Aquaponics Training (Special Offer in right sidebar of this email), where you will learn more about real-world operation of a commercial aquaponics system than you can anywhere else in the world. For smaller home backyard and apartment systems, please read on:
Construction Plans and Operating Information for 4 Different Sizes of Apartment/Condo Aquaponics Systems $49.95

If you want to learn aquaponics easily and inexpensively, the Indoor System package is perfect for you. It includes new and easy-to-understand building instructions and complete operating information for 4 diifferent sizes of small aquaponic systems based on our years of experience operating a commercial aquaponics farm. Anyone can build a system out of plastic barrels, but operating one without good and easily-understood information can be frustrating. Operating information is given in the form of a "Daily Operations Manual" where you simply use the checklist and follow the step-by-step instructions on your way to success with aquaponics.

We've spent hundreds of thousands of dollars, hundreds of hours, and built our first commercial aquaponics systems with FAR less information than this manual contains. We included all the information learned from spending that money and time in this manual so you don't make any of the same mistakes we did.

Learn about our Apartment/Condo Systems!

Aquaponics Nugget #20:
Water Quality and Testing (Part 2 )


We measure pH with a VitalSine pH meter from Aquatic EcoSystems (catalog #VS99), which is also good for thousands of tests (pH strips ALSO cost $0.50 each test). Optimal pH for plants is 6.0 and for fish is 8.0 so we compromise on  a pH of 7. pH in these systems changes slowly, always towards the direction of acidification (lower pH numbers) so when we see a pH going down into the low 6-range we add  a pound or two of calcium carbonate to the system to change the pH upwards towards 7. You may be able to hurt it by adding too much at a time, but it is difficult, as this carbonate tends to simply precipitate out of the system and lay on the bottoms of troughs or tanks when the pH gets to about 7. It then reabsorbs into the system when the pH goes down over time. When you make additions just do them a bit at a time instead of a barrel.


Low limit for iron is when you see yellowish new growth on plants. Add iron. We add a pound or so of 13% iron chelate each time we see yellow growth, usually about once every month or two. It's very satisfying: the plants green up sometimes within six hours or so of the iron going into the system. It's taken us a year and a half to go through a 25-pound bag in our commercial operation with five systems.

The "Mystery" of Nutrient Levels in Organic Aquaponics Systems

Even though they never vary more than a few ppm, we test measurable nutrient levels in our systems. With all due respect, the university aquaponics establishment (UAE) knows little to nothing about what the nutrient cycle, recommended nutrient levels, or actual nutrient availability is in an organically certified aquaponic system such as ours because they've never had one.  They use pH adjusters in their systems to adjust pH swings (calcium hydroxide and potassium hydroxide, neither of which is organically certifiable) which we feel artificially manipulate these systems into extreme measurable nutrient swings, but DON’T actually provide more usable nutrients for the plants. We used these chemicals for the first few months until we went organic and started using an organically approved buffer chemical, calcium carbonate (coral beach sand).

During the few months we were using the hydroxides, we experienced the same pH swings the UAE documents in their literature, and had to adjust pH as often as every three weeks or so. According to one of the main program authors there, they had periods when "we had to adjust pH every two or three days for a couple of weeks at a time". While on the hydroxide pH adjusters, our systems would have nitrate swings from 40 up to 160 ppm, that weren't obviously related to the pH swings, but we were suspicious. When we switched over to the organic buffering chemical we noticed that we only needed to adjust pH every four to six MONTHS; and that pH tended to be rock-steady for months at a time. We ALSO noticed that the nitrate levels in the systems no longer had these huge unexplained nervous swings, but rather were rock-steady at 3-5 ppm year-round, with an occasional HUGE jump to 10 ppm.

The hydroponics guys hate these numbers and tell us we're lying; even the consulting aquaponics establishment claims that 60 ppm is the minimum desired level for nitrates in aquaponics systems. Unfortunately, none of these aquaponics people can demonstrate a way to dependably and accurately adjust nutrient levels in their systems. This is because measurable nutrient levels in an aquaponics system are the result of a complex arrangement that I don't believe they understand yet, let alone understand how to manipulate. We've been organically certified for two years and we're just beginning to have a good handle on it. We believe what was happening in the UAE systems when they adjusted pH with these highly caustic chemicals (hydroxides), was that each time they added them, they killed off the majority of their nitrifiers. What happened then is that they would get a nitrite spike when the nitrifiers reestablished, along with a nitrate spike, which accounts for the major swings in nitrate levels these systems experience.

The main reason for our conclusion here is that even in our ORGANIC systems, with no hydroxides anywhere in the neighborhood, we still see these swings. But they only happen ONE TIME in the operating life of a system: at system startup ONLY. At the startup of one of our organic systems we will typically see a nitrite spike of up to 10 ppm for as long as two weeks or so, accompanied by nitrate levels of up to 40-80 ppm, lasting up to two to four weeks after the nitrite spike is over. After this initial period of high nitrate levels, the system nitrates decrease to the previously mentioned 3-5 ppm with occasional 10 ppm, never varying out of this range in years of operation.

To be completely accurate and not make an unsupported blanket statement, we need to qualify this by saying we've experienced this in our water temperature range of 70-76 degrees F. We don't have personal first-hand experience of this phenomenon in warmer water or colder water. We suspect it might look like a higher range of nitrates in warmer water, and a lower range of nitrates in colder water than ours,

(Next week: "Part 3" of this "Water Quality" Nugget, including approved organic system additions).

Regular Free Workshops

Lettuce in the Small Commercial System
Aquaponics grows more for less water, work, and energy; and is more fun!

We're holding a free workshop on our farm every Saturday focused on growing your own food with aquaponics and also with permaculture. These workshops will start with a one-hour free farm tour from 10-11 am, then the free workshop from 11-12. Sample topics include: "How to grow"; bananas, sweet potatoes, taro, green onions, tomatoes, and so on. Each workshop will cover a different vegetable and include a handout with instructions covering that vegetable for you to take home. Click here for information. See you there!


Installing the liner in a hydroponics trough.


Installing a hapa into a tilapia breeding tank.

Special Offer! Sign up for our October 4-7th, 2010 Commercial Aquaponics Training now, and we will email you  our Micro System package so you can begin studying aquaponics! ($99.95 value)

Sign up for Commercial Aquaponics Training

In The Farmily

One of the big questions we are asked at our farm tours is: "Can I feed worms, black soldier fly larvae, bugs from bug traps, etc to my fish". The next question is often: "Can I put (chicken manure, pig manure, horse manure, compost, compost teas, supplements, fertilizer, worm castings, etc) into my aquaponics system?

If you are concerned with organic certification, Food Safety Certification, making money with aquaponics, or just plain NOT getting sick from eating the vegetables coming out of your system, don’t have ANYTHING to do with: duckweed, crawfish, black soldier fly larvae, worms, any kind of warm-blooded animal manure, chemical fertilizer, or effluent that someone says you can safely add to an aquaponics system.

Even if you don't care about the certifications, the manure and effluents are a GUARANTEED source of E. Coli; duckweed will spread throughout your system and cause all kinds of problems later when you are processing and packaging vegetables. Depending on where the "base" you use to grow your soldier fly larvae came from, it can bring in E. Coli to contaminate your system.

Crawfish are just like piranha with opposing thumbs! If you EVER get crawfish into your systems, you will be raising crawfish (and only crawfish) FOREVER, because they are near impossible to eradicate, and eat everything in the system! Their eggs are so small they pass through any filter you can devise, and will end up throughout your system. Be careful if you try any of these things, and try them in a small, easily sterilizable container or aquaponics system!

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This email, our manuals and construction plans are all copyrighted by  Friendly Aquaponics, Inc, Susanne Friend and Tim Mann, 2008-2010

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Friendly Aquaponics, Inc
PO Box 1196
Honoka'a, Hawaii 96727

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