What Doesn’t Work, Part 2:
Here’s an additional list of system components, techniques, and ideas for systems that we know don’t work, OR can have serious problems when applied on the commercial level, with some of the reasons why. For more information on this, see What Doesn’t Work.
(Below) A banana tree and a pineapple plant in a 64-square foot Micro System; one of our experiments that DID work.
Here’s a short list of the experiments our students have tried, with the “fix” in bold at the end of each item:
- A student listened to the salesperson selling them water pumps and blowers; and rather than just get the correct one from the materials lists we’d included with the construction manual, they bought what the salesman was selling. They ended up with huge overloaded hot blowers that used four times as much electricity as necessary; and huge water pumps that pumped four times as much water as needed, and it overflowed out of their last trough because it couldn’t flow back to the sump tank fast enough through the PVC pipes that were correctly sized if they had used the correct water pump. Just get the right size pump or blower to begin with!
- A student of ours started his aquaponics system with an existing “catchment” water tank that was under a tree; this tank had 6” of dead gunk and leaves in its bottom. This stuff then got pumped out into the troughs and the rest of the system when the owner turned on the air and water pumps. The water in the system stank, the ammonia level was through the roof, and this system “wouldn’t startup”. Start your system clean! Don’t put extra organic material in there for the “nutrients”; you will only drive the ammonia level through the roof!
- If you put black soldier fly larvae, worms, compost, or any kind of warm-blooded animal manure into your system, they are an almost guaranteed source of Coli, which can kill people if consumed on uncooked food. If your Organic Certification agency or Food Safety Certification agency finds out you ever used these (even if your water tests OK), you run the chance of losing your certification. Don’t allow contamination of your aquaponic system with BSF larvae, compost, worms, or animal manure; you can lose your valuable certifications!
- Duckweed will spread throughout your system and will double or triple your labor required to clean and package your crops later when you are processing and packaging vegetables. Its actual protein level, based on its “wet weight”, is 2-1/2%; this is because it is 92% water! Don’t EVER allow duckweed into or near your systems. Period.
- “Effective Micro-Organisms” AKA “EM”, “Beneficial Active Micro-Organisms”, AKA “BAM”: Regardless of what the salesperson says, EM and BAM are bacterial cultures that are foreign to aquatic ecosystems (which is what an organic aquaponic system is), and they will kick the system out of balance, doing things like killing all the plants, making the roots go black, etc. They may have a beneficial application, somehow, somewhere in aquaponics systems, but we don’t know about it. What we DO know is that experimenting with things like this in large commercial systems can be very expensive! Easy fix: don’t do it!
- 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 nearly impossible to eradicate, and will eat everything in the system! They leave the water at night and will crawl across short intervening spaces to inhabit nearby systems and tanks that previously didn’t have crawfish in them. Their eggs are so small they pass through any filter you can devise, and will end up everywhere. Easy fix: don’t bring crawfish onto your farm!
- About adjusting the pH downwards with “chemicals”: although there’s no need to do it (because an aquaponics system does this automatically by itself), people still feel the need to adjust pH down, and end up using things like phosphoric acid, vinegar, and citric acid. Citric acid is an organic herbicide; putting it in your system for any reason at all will make the plant roots go black and kill all the plants. Easy fix: don’t do it!
- We adjust the pH upwards in our systems with calcium carbonate (coral beach sand in Hawaii, crushed oyster shells elsewhere) at the infrequent times they need this done. Potassium carbonate can be used to help buffer pH, but it is not an organically-approved material, and we have one instance of a student poisoning his system with too much potassium carbonate, ending up with potassium toxicity, and having to dump all the system water and refill. Easy fix: don’t use potassium carbonate!
- If you invent something new like these things, please contact us and let us know what you did and how you fixed it, so we can share it with new students and spare them the same suffering! (We’ll omit your name, of course, unless you want us to print it!).
MARC says
I have been considering growing crickets and using them to supplement the food source for my bluegills and yellow perch. The crickets can convert some of the green waste from the system to protein with a good conversion rate. Have you considered this? What are your thoughts?
Tim Mann says
This question gives us a great opportunity to discuss what aquaponics is REALLY about, which is NOT about focusing on a microscopic scale on individual parts of the process, but rather about YOU becoming a “systems thinker”. What’s that?
That’s someone who can take a step back and look at an entire ecosystem (which is what an aquaponics system is), and understand the various parts and pieces and how they relate to each other. Someone who does this really well can improve on the system; conversely, it’s VERY difficult to improve on any system unless you become an accomplished systems thinker.
As this post is about “What Doesn’t Work” when applied on the commercial level, I’d have to say that crickets really would NOT work. Not because they’re not a good fish food; they are. Not because they’re not sustainable; they are. The reason they won’t work is that they’re too expensive!
To feed your fish crickets, you first have to put together a “cricket habitat” to breed and house your crickets in = expense #1; then you supply labor to harvest the green waste and feed it to your crickets = expense #2; then supply more labor to harvest your crickets and feed them to the fish = expense #3. So you will have certain expenses, and will invest a certain amount of labor in feeding crickets to your fish. What will those expenses be? How many crickets do you need per day?
We feed our fish in 6,000 square feet of aquaponics about 20 pounds of food a day. At $1/lb, this costs us $20 per day. Now, we go to the pet store (the only place I know that sells crickets), and find that crickets cost $85 per pound. Cricket flour (yes, look it up on Google!), which is dried crickets, sells for $20 to $40 per pound.
Now, the sales price of anything is a good indicator of how much expense and labor went into producing it; so I’d have to say that feeding your fish crickets on a commercial scale is going to cost you around $40 per pound of “not” dried crickets. If we did that, our food bill would be $800 per day! We’d be out of business in around two months!
That last was a clue to the most important part of this question: as much as we all want to be sustainable, a business that does not make a profit, and is not here next year to keep doing good, is NOT sustainable; however much its individual business practices were. It’s dead, just like the dodo and dinosaur. You have to run your business so it STAYS in business!
What you can do is begin experimenting; and when you find a method and a “cricket” that is cost-effective, let us all know. The price of fish food will continue to rise; and that will make your crusade for crickets more feasible all the time, as you develop better and cheaper ways to grow and formulate alternative fish foods.
Aloha, Tim…….
Bill York says
I would like to know if you have tried or know of any attempts to grow wasabi using aquaponics. I have not found anyone online. I think this would be perfect for aquaponics and would like your thoughts on doing this.
Tim Mann says
We’ve never tried it, and want to. The problem with wasabi is that it likes COLD water, small amounts of sun, and is fragile. We have 70-degree water in the winter, and it warms up from there; so it’s nearly impossible for us to get the 50-60 degree water that is desirable for culturing it.
Here’s two good links to find out more about wasabi: http://www.realwasabi.com/cultivation/index.asp and http://www.wikihow.com/Grow-Wasabi
If you do try it and have any results at all, please let us know.
Aloha, Tim……….
Andrew Trefethen says
So, I’m looking at http://old.friendlyaquaponics.com/2015/12/28/what-doesnt-work-2/. There is a wonderful photo of a banana tree that worked! But am curious about the big rock next to it. What purpose does the rock serve? A weight to keep the wind from taking it away?
Tim Mann says
That’s a good question!
This banana tree is so heavy it doesn’t need a rock to hold it down; in fact, I had to cheat and put a concrete brick under another banana tree in the same system, when it got to about 8 feet tall and was sinking the raft. I also needed to tie it to the tomato trellis in that trough so it wouldn’t capsize the raft!
It may have been a “special rock” that Rose or one of the “littles” put on the raft for some kid reason.
Aloha, Tim…….