As someone who gardens, and has a little 3 acre homestead, this is not something I would go for in its current state... but there are improvements that could get me there:
1) I understand buying off the shelf parts for your prototype. But spending hundreds of dollars to be shipped parts I could have bought myself is just adding more middle-men into the supply chain. At this point, just sell the parts list and plans for $20. And when you have built parts with ease of assembly in mind, so this is 5x easier than DIY with parts from home depot... THEN sell the kit.
2) You need to share data of how much water is needed on an ongoing basis, in different climates. People in Arizona with limited water supplies might not have the same resources to put in, for example.
3) You need to talk specifically about what plants work well, what the yields are,in different climates and growing zones, and recommend planting strategies for different locations.
1. In talking to other aquaponics businesses, I've heard that people are not very excited about paying for a manual/plans. If you're serious about this, let me know and I can email you a payment link :)
2. Aquaponics in general only uses ~10% of the water a normal garden, with the only water losses being evaporation and plant transpiration (and what water is incorporated into the plants themselves).
3. This is a good point. The plants that normally grow well in your garden will grow well in aquaponics, with a few extreme exceptions. For example, you would not want to grow blueberries, since they prefer a low pH.
I love the idea, but as an Arizonian, evaporation is a serious concern - in the summertime, water evaporates out of pools at a rate several times faster than more moderate climates (pool covers are big business out here for that reason). When we water lawns/gardens, it's generally in the very early morning or late evening, when we won't lose a large chunk of the water to evaporation.
I'd also be concerned about water temperatures of a shallow pool during the summer. Water's a great heatsink, but that can be a problem when the ambient air temperature is 118F, and the intense UV out here will likely break down the pools quickly. Most anything made out of plastics is completely trashed after a year of exposure out here. PEX in particular isn't rated for continuous UV exposure, and would likely disintegrate rather aggressively out here.
I love the idea, though. Turnkey aquaponics is a really exciting prospect, especially out here where we don't have particularly rich soil. I'd love to be able to run something like this in my backyard, if I could work out the location-relevant logistics.
If evaporation is a serious issue, you could cover up most of the fish tank (but be sure to add an air bubbler so there's enough oxygen for the fish). Also, if you dig a hole for the fish tank (like I didn't) that should help with the water temperature. In your case, tilapia would be a great fish to grow, they are really happy with water above 85F.
Also, it would be a good idea to cover up the plastic, perhaps even more than my enclosure does, to ensure it doesn't degrade as quickly.
I'll help customers make these and other design considerations as part of AutoMicroFarm support.
> but be sure to add an air bubbler so there's enough oxygen for the fish
Not a serious aquarist here, but I did a lot of research before getting my little 10 gallon tank at home set up and everything I've read says the oxygen introduced by air bubbles in the water doesn't really dilute in the water well (most of it just comes up the bubble and out into the open air). In theory, as long as there is a big enough hole for a modest amount of air to be exchanged with the surrounding environment you shouldn't need any extra equipment, as the surface of the water should continue to exchange oxygen and carbon dioxide just fine as long as there is enough oxygen present.
What really matters is the surface agitation. Bubblers will do that, but so will any pump as long as the outflow is directed toward the surface.
A better idea, I feel, is to just keep a layer of air between the water surface and the cover. The key issue is that oxygen has trouble crossing the air/water boundary, so you want that to be as big as possible. Meanwhile, if you keep the air holes in the cover small enough, most of the humid air will be trapped inside, and you will minimize losses from evaporation.
Another factor to consider is the air pressure. If you cover up the fish tank, and add the air bubbler, the pressure will increase, which will increase the dissolution of oxygen into the water.
We have possums. They don't go through our bins, but they scour leaves from trees (until the tree dies) and make demonic noises at night: https://www.youtube.com/watch?v=cHulXzuc_9Y
They look cute but would tear you to shreds. And you are absolutely right, they sound like demons. When I was younger they really freaked me out till my parents told me that was what the noise was.
Seriously impressed by your answer to Q #1, kudos! ("I see no market there, but feel free to prove me wrong")
A bit of feedback: can I suggest including a bit of information about the project and aquaponics in general? It took me a while to figure out what this is all about. Something like "Grow your own food with minimal hassle" would help a lot.
EDIT: your answer below nicely sums it up, you might want to put it on the homepage: "Here are just a few advantages over a traditional garden:..."
Huh, I didn't realise you had a separate landing page (which btw. displays a HTTPS certificate warning when you go to https://www.automicrofarm.com/ - you might want to fix that, lots of users still type the "www" at front of addresses). How about linking to it from blog page?
Landing page looks much better, though I would suggest replacing the top image with the photo of the system (because it takes quite a lot of scrolling until you see the solution). Also, I miss info where you ship to - EU too?
Ok, sorry, this reply looks like I am dissecting your web page... professional deformation I guess. I don't mean any harm. ;)
Congrats on your achievement and good luck with the project!
The whole premise of aquaponics is that you don't need soil, just something that holds the roots in place and allows fish waste to be converted to plant fertilizer by the bacteria.
> At this point, just sell the parts list and plans for $20.
That will lead to a huge support headache, I can really see the case made to send a complete set so that it will be reasonably easy to help people with troubleshooting.
Substitutions may be no-ops or they might change the whole system in subtle and hard to predict ways.
I like "For $25 you get the plans and some pics and access to our user forum where you can get advice from others like you but you get NO SUPPORT from us. However! If you later decide that you want the full kit, we'll rebate your $25 on that order!"
I went the easy (and hopefully more value-adding) route. You can download the parts list and manual for free, since I just open-sourced the AutoMicroFarm design. I am also offering optional support. See more on the AutoMicroFarm site: https://automicrofarm.com/
> As someone who gardens, and has a little 3 acre homestead
Unrelated to aquaponics, what do you find the effort/yield is on that?
I've always found with anything larger than a small garden is I'm basically buying a job that pays less than $10/hr. So I've never really felt the urge to go as big as 3 acres since I'd feel that was more than a hobby.
> 1) I understand buying off the shelf parts for your prototype. But spending hundreds of dollars to be shipped parts I could have bought myself is just adding more middle-men into the supply chain. At this point, just sell the parts list and plans for $20. And when you have built parts with ease of assembly in mind, so this is 5x easier than DIY with parts from home depot... THEN sell the kit.
I've have to agree with this as far as routes go. DIY home assembled aquaponics is a pretty common topic that has plenty written 'bout it. It just isn't worth buying a kit without both of:
A) Detailed input/outputs & cost/production for multiple geographic areas so the TCO and lifetime product is basically known. (i.e. Substantial risk reduction greater than the cost of the middle man. The only margin on DIY is the experimentation phase.)
B) An actual kit that is substantially cheaper and/or easier than Home Depot and DIY. In other words, in addition to the reduction of risk due to better info, it also needs to be cheaper in at least one dimension than DIY.
We do produce a lot of our own food, but give up much of our free time to do it. On the other hand, we are not dependent on the standard grocery store supply chain in this country, and while that is worthless right now, there are potential future scenarios where that is priceless. But mostly, we do this as a hobby and so that our kids know how to produce food, whether or not they choose to actually do so when they grow up.
But in all seriousness, yeah, I get that. I keep emergency supplies (90 days/person of backpacking food + water + filters). I also cycle the emergency supplies faster than they expire due to my interests (Food, hiking, computers, books are the sum total of my hobbies) so I find its a good balance point for me since I don't really expect a supply chain disruption would last substantially longer than 90 days.
The market for this is probably too small for the business to be viable at a $20 price point. Also, because a $20 plan and parts list isn't much of a commitment, most of the small group of people who buy it won't end up building it, and so the business will have minimal opportunities to generate success stories or, for that matter, to iterate.
In India, especially with pesticides and other pollutants, there is a strong need for good, clean food source. There is severe water shortage. Labour and materials are cheap. There is a rising need for healthy snacks. This has a good chance of taking off here, especially the urban pockets.
> At this point, just sell the parts list and plans for $20
I'll do you one better: you can download the parts list and manual for free, since I just open-sourced the AutoMicroFarm design. I am also offering optional support. See more on the AutoMicroFarm site: https://automicrofarm.com/
* Sand is not a good substrate for plants. Too fine - aeration problems; surface to volume ratio not good. Anaerobic zones will form. Denitrification with odor will stress plants and fishes.
* No dedicated biofilter. Nitrification bacteria will form and live on the sand. Tight coupling between fsh tank and grow beds. No way to decouple when one or the other has to be maintained.
* Fine mesh preventing the sand to get into the fish tank will clogg with detritus.
* Grow beds will clogg with detritus after approximately one season.
* No sump tank. Water level in the fish tank will vary a lot. Fish don't like that. Stocking density will have to be low to aleviate this.
* Too much sun on the fish tank. Most fish species don't like this and algae will form rapidly.
Please do not _sell_ aquaponic designs like this one.
I'm doing aquaponics since 2012 and I'm currently working in aquaponic research for a university.
The sand-based system is based on Dr. McMurtry's aquaponics research at NC State University. Here are a list of publications about it: http://iavs.info/publications/
* In general, course sand is a great substrate for plants. Both research and my own experience show no problems with aeration or anaerobic zones forming.
* The sand is the biofilter. This does form a tight coupling of the system, but does not prevent regular maintenance. For intensive maintenance, you would need to take the fish out of the fish tanks anyway.
* No clogging has occurred so far because of the mesh.
* What length of time is one season? What will happen after one season that won't happen after X days/weeks/months?
* The water begins draining from the veggie beds seconds after the flooding cycle starts, so the water level in the fish tank only varies by ~10-15%.
* How rapidly will the algae form? Two months later, I don't really see algae forming in the fish tank. There is algae growing in the furrows, but that's a good thing, since algae forms a natural nutrient battery. In any case, the fish tank placement is not optimal in my prototype, and can be improved in subsequent installations.
Thanks for the pointer to Dr McMurtys research. Will read.
Sand might be a good substrate for hydroponics, but with aquaponics, especially when you are not removing the solids prior to flooding the beds, I doubt you will run the system at optimal performance.
Regarding this and the clogging topic I'd like to know at what stocking density you have been running your systems. Our experience so far is that systems are easier to run stable with low stocking density and low feed intensity. This is a valid approach for home systems, but results in lower yields.
When you start raising stocking density and feed intensity, the nutrient concentration becomes more attractive for the plants. But then solid removal becomes quite important. I am pretty sure if you simply pipe the aquaculture water into sand beds without prior processing, solids will accumulate in the grow beds.
You're saying that you did not have any problems regarding aeration. Did you measure DO and nitrites? How does pH behave in your system? Does it drop, rise or stay constant?
"What will happen after one season that won't happen after X days/weeks/months?"
Experience from other researchers with ebb and flow show that even with gravel and LECA sludge builds up in the grow beds and that starting from the second season this can become a problem. Then the grow bed has to be dug out and cleaned from sludge.
"How rapidly will the algae form?"
We recently built a system (on customer request) that has a lot of light on the fish tank. Algae built up after two weeks. Massively. Again, low algea formation in your systems might be due to low stocking density. If the plants have a chance to consume the nutrients and therefore keep the nutrient concentrations low enough to prohibit algae growth, then it might appear ok. But then you are starving the plants, reducing yield.
I've only been running the system a couple months, and haven't seen any problems. Of course any system will need maintenance, but in this case, it's on the order of once every couple years. Here's the relevant link: http://iavs.info/commercial/sand-is-amazing-but-its-not-magi...
I don't have a DO sensor, but I do measure ammonia, nitrates, and nitrites. There were the predictable spikes in ammonia, then nitrites, then a smaller spike in nitrates that you get in a typical aquaponics startup cycle. My pH started out high (~8), and is slowly dropping. It's around 7 now.
Like I said, I know my tank placement with respect to the sun is not optimal. I think the reason I haven't seen algae growth in the tank is because the water is not clear because of the sand fines. The water should clear up once the biofilm/algae gets more established in the furrows; maybe I'll see some algae growth in the tank at that point.
What's a better inexpensive substrate? I've been finding Diatomaceous Earth (sold as kitty litter or oil absorbent) to be great for starting seedlings, but it's more expensive than desirable for filling a large volume.
You're wrong, it is 100% recyclable[1]. Otherwise we would have an enormous heap of those things.
It's not composted, but luckily these things can be recycled into other, more useful products. You basically can't sell compost over here as there is too much compost already. We're already exporting compost to the UK for very low prices.
For ebb and flow grow beds expanded clay (LECA) or three quarter inch gravel are proven to work well. Make sure beforehand that your substrate does not change pH.
Cat litter stuff or Seramis is to finde grained for the grow beds.
Hi HN, Andrew here. I'm the AutoMicroFarm founder. Really happy to finally have this prototype finished, and available. Let me know if you have any questions!
Hopefully you can partner with installers in metros such as the Bay Area who can help less industrious folks get up and running. Amazing what a difference that decking makes :)
I was thrilled to see you're an RTP-based company. I'm on the other side of Raleigh from you, but I shared this with my community and now need to do some measuring to figure out how much grading I'd have to do to install one of these and then figure out what my HOA would say. :)
Have you gone through a winter in this area with the unit in a greenhouse? Any reports on how that worked out?
Waves Make sure to mention the free installation to your community! (I may limit this to a small initial number of customers, we'll see how it goes).
I have an HOA, as well. In our bylaws, we're allowed a garden of 50 square feet without explicit permission, so I didn't apply for an arch. request. But I'd be happy to help any customers apply.
My first prototype was in a greenhouse in Cary. I was able to continue growing through the winter, but everything (understandably) grew slower. See my previous blog posts for more detail: http://blog.automicrofarm.com/page/3
How many of these would you need to produce enough food for one adult? What kind of fish should you grow, and how long do they take to be adults and edible?
Your project is very cool, I think you're doing an amazing job. Keep it up!
If you eat mostly plants, two of these systems will provide 90%+ of your food (assuming you have a greenhouse to put it in, or live in a place that stays warm year-round).
The fastest-growing fish used for aquaponics is tilapia, which can reach maturity in six months. But, they require for the water temperature to stay above 60F (15C), and really prefer water above 85F (30C). Other fish take 9 or more months to mature.
My initial proof-of-concept produced 10 lbs/square foot annually, not counting the fish. This system should be more productive, but only time will tell.
If this system has similar levels of productivity, it would produce 360 lbs annually, so two systems get you 2 lbs of food daily.
Apart from the aspect that I consider this design to be flawed, I can give you some rough estimates on yield.
A sound stocking density for tilapia would be around 50-60 kg/m3. If you keep temperatures high (28-30°C) you can have two harvests in one year. Tilapia has approximately 40% filet, so you can produce roundabout 50kg of edible fish fillet in one cubic meter fish tank.
With such a fish tank you can approximately produce nutrients for ten square meters of grow beds. A realistic estimate for the yield would be 10kg of produce per square meter per year, maybe a little higher if you take good care of the system. So that would give you 100-150 kg of produce per year with a 16sqm green house, a one cubic meter fish tank and ten sqm grow beds.
The recommended consumption of produce is 100-150 kg per year. So your system could cover your produce consumption for one person.
You still need carbohydrates (grains) and oil (rape seeds and sun flower and such) and protein. The fish will not cover your protein demand.
You'll also have to keep in mind that depending on how you run the system you'll have a lot of fish twice a year. Staggered production is not possible in one smallish fish tank.
There are a lot of indoor options available, but they are pretty small in size, and might produce a salad a week at the most. That's really not AutoMicroFarm's vision.
If you are thinking something that's larger in size, that's a possibility in the future. AutoMicroFarm would have to solve the issue of the weight (the water and sand in the current system are about 1.5 tons). Also, the cost of the LED lighting would have to come down before it is affordable.
I'm being 100% serious here: Have you thought about the market for the smaller one being more oriented towards cannabis rather than vegetables?
With Colorado and Washington state (and I believe Alaska) now allowing homeowners to legally grow cannabis, I think a smaller version of this product for indoor use would have a market. It doesn't have to produce a large yield, and people would really like the aesthetic aspect of a closed cycle with fish involved.
This looks really neat. I wish I had a yard to put it in. If I move someday, I'll certainly try to remember this.
Can you explain what makes it better than planting a traditional garden? I came away from the page with the impression that it is better, but I'm not entirely sure what makes it so.
1. Are you in California? If so, can you comment on how easy/hard it is to get Tilapia for a setup like this? I know someone living near Campbell who had trouble legally getting any of the Tilapia species that are suitable for aquaculture. The California department of Fish and Wildlife apparently considers most or all Tilapia to be invasive species. (Oddly enough, I see T. buttikoferi in pet stores every now and then, but they're too expensive to eat.)
2. Is using PVC really that bad? I've been in the aquarium hobby for over half my life now, and I can't remember ever seeing a single DIY aquarium plumbing project that didn't use PVC. PVC seems particularly ubiquitous for elbows and fittings--how hard/expensive is it to get PEX fittings at retail?
1. I'm not in CA, but from what I read it seems like raising tilapia in CA would be legally difficult. You do have other fish choices, such as catfish crappie, perch, and bluegill.
2. I haven't been able to find a lot of hard facts about PVC, other than the fact that it supposedly bad for fish you want to eat eventually. In any case, PEX piping and fittings are readily available online and in Home Depot and Lowes stores.
PVC-U is just fine for aquaponics. It can be considered food safe. PE is nicer to recycle, but when you have a sound system design you are not going to change and discard pipes very often.
You would need to either locate it in a greenhouse, or just shut it down over the winter by harvesting fish and plants, and letting the water drain away instead of into the fish tank.
I was coming here to ask that. If this were in some sort of greenhouse would this be sustainable for years at a time, or is it more designed to be something you start up each spring?
Also, may have missed it, but do you plant the seeds right into the sand or sprout them first somewhere else? (I know basically nothing about gardening, sorry)
Great idea, and very tempting when I get into a new house.
The easiest way to get started is by planting the seeds into the sand, just push them in with your finger. I did plant sprouts in about half of each veggie bed, but I had to wash dirt off their roots, which really put them into shock.
The climate in our house varies so much that we need a heater in the winter and a cooler in the summer to keep it habitable. An additional grow room for plants would require the same and the cost would seem to outweigh the benefits, although I'm willing to be convinced otherwise.
Those are some amazing links. Definitely some inspiration for the future. I could definitely see this getting tied into a system like in the second link, with compost and chickens, and all that.
There's a YouTube channel "Bigelow Brook Farms" where the broadcaster designed and built a geodesic dome greenhouse (lots of passive solar) and does year-round aquaponics. I think he lives in Delaware or somewhere in the NE USA, it definitely gets cold there. He has 4-5 years worth of growth in this greenhouse and lots of lessons learned. I recommend it if you're interested in the topic.
Very cool concept. I would like a bit more information on the following:
1) What kind of fish are recommended/suitable?
2) Where do you get the fish? I assume most pet stores don't sell fish to raise for food.
3) What are the fish food options? Again, I assume pet stores don't carry the required feed.
Edit: A few more fish related questions:
Do you have to stick to one type of fish at a time?
How many fish can your kit support at one time? I'm sure that's species dependent, so perhaps some examples?
1. Tilapia, perch, and catfish are popular. I have catfish in mine. You just have to match the temperature requirements to your climate/area.
2. You would get the fish at a fish hatchery, there should be one near you. This is something I find out for my customers. You can also buy fish online, but the overnight shipping makes it a bit expensive.
3. You can buy fish food online, or at a hatchery, or e.g. Tractor Supply.
4. The thing about different fish species (or even same species but substantially different sizes) is that if a fish fits inside a bigger fish's mouth, that bigger fish will try to eat it, unless the smaller fish has somewhere to hide, like aquatic vegetation. This is something I will be experimenting with more.
Realizing this touches several comments made already...
- What about pests? Will the fish control mosquito-larvae in the pool? ... and any other bugs that fall in? (Think southeastern US or other places where mosquitos can be a problem.)
- What about scavengers? Do the fish bed to be protected from raccoons out suburban/feral cats?
- Can you sell sub-kits? For example, I could use your source of kiddie pools and fish, but don't need to buy pex from you when there's a hardware store two miles away...
- What about erosion during times of hard precipitation? (Again, most places in the US do get some serious weather multiple times during the growing season.) Seeing my mature plants wash away would be rather frustrating.
I dig the idea, from one garden hacker to another, I just have a lot of questions ... and as I said: I'm not interested in a full kit, but a sub-kit with research would be really useful.
- In my experience, the fish do a very good job of eating any mosquito larvae and other insects that happen to fall into the pool.
- Depending on how you would want to set up the AutoMicroFarm, there would be plenty of hiding places for the fish. In my setup, I only see the fish come out of hiding when I feed them. But, if this is still a concern, you could add a simple net to deter predators.
- I thought about selling just certain parts, but that adds too much complexity. If you're serious about wanting just certain parts, email me and I'll help you out.
- We've had several hard rains and high winds, and I haven't seen any significant erosion... maybe a few grains of sand that got washed out, but that's it. The plant roots are really good about holding on to the sand. :)
If there are raccoons in your area, you really want netting over the pond.
The standard advice for preventing fish loss to raccoons without using netting is: the water must be at least three feet deep (any less than that, and the raccoons will hang from the edge by their hind legs and grab sleeping fish off the bottom) and you MUST NOT train your fish to surface near the edge of the pond (fish have trouble distinguishing the sound of human footsteps from the sound of raccoon footsteps). Any food should be thrown into the pond at least three feet away from the pond edge.
Naturally, that advice isn't very helpful for a pond six feet or less in diameter.
That looks similar to a barrelponics system. That was my first, proof-of-concept prototype. It cost me $700 and 50 hours of work, and had a growing area of ~9 square feet.
I'm sure you could get the system cheaper if you found the parts for sale, or already have them. You could also build it faster if you're really handy, have the experience, and don't make any mistakes.
Very little maintenance after the initial assembly and planting, and I've had pretty great results so far.
I've heard about aquaponics before, but never dug into it. I'd be interested in hearing about its advantages over a (presumably less involved) traditional container setup like mine.
Hey Josh, the advantages are similar as compared to a garden, except the containers solve some of the problems (such as optimal watering). Probably the biggest advantage is you get fish as part of your harvest.
If this type of thing piques you interest, there is a vibrant aquaponics community with many forums eg. [1] and designs using all sorts of off-the-shelf parts.
IBCs and blue plastic drums are generally the "go to' solution [2] as they're made from HDPE, although some are made from plastics that are not considered food safe as they use mould release agents during the manufacturing process which are toxic (no reference for this at the moment, sorry).
Just be aware that generally you need A LOT more grow bed area than you would think to be able to efficiently use the fish tank volume. You can pack a lot of happy fish into a given volume of water.
Also, the general consensus is to use course gravel (20mm) rather than sand, as sand can quickly become blocked with organic material.
[EDIT] Also, you'll want to keep the sunlight off the fish tank, because once the nitrogen level starts to rise [3], the algae will go nuts in there. I learned this the hard way.
I realize the gravel vs. sand debate is a bit contentious, but I haven't had any blockage in the two months I have been running the system, despite claims of that the sand will become clogged within hours or days.
In fact, the sand media was the original aquaponics design.
That's good to hear you've been having success with sand.
I'd love to hear how it's going after 12 months, because sand is certainly easier to work with than course gravel, which can be difficult to plant seedlings into, based on my own experience.
Was the kiddie pool chosen specifically for cost? There are a plethora of fiberglass and UV-stabilized PET plastic holding tanks used in the aquaculture business (and rainwater collection systems) that would have much better strength and lower tendency to go brittle over time.
How much more would it cost to use something that's at least a solid color (preferably green/black/brown)? The obvious kiddie pool factor is a big enough turn off for a lot of people that fixing it might be worth raising the price point. Even the wooden enclosure doesn't hide the color and print on the pool.
As soon as you have any sort of volume, you could hit Alibaba and try to find something better, even get your items customised to completely suit your needs.
The colour/look would completely put me off buying.
At a guess, because it collapses to almost nothing. The holding tanks are huge (I've used a couple of the 1,000 litre ones) and you can't easily get rid of them when you want to.
They don't really, though. If you try to collapse a kiddie pool it will be permanently damaged due to the stresses on the plastic. They usually ship in a box the same size as the uncollapsed pool. The holding tanks come in all sizes - you can get them the same diameter and depth as a kiddie pool, just obviously thicker and heavier since they're actually designed to hold the weight of water without deforming.
I presume you need to manually top off the system for evaporation?
In rainy weather, is losing nutrients to overflow a problem?
Any thoughts to using a 12VDC pump, powered by a solar panel and small battery? (In some places it is illegal to have an extension cord outdoors for months on end.)
Would it be easier/cheaper to ship a version that didn't include the kiddie pools or sand, with the expectation that someone could source those bulky items themselves?
It's hard to find a 12" (30cm) deep medium that would allow for fruiting plants such as tomatoes, be lighter than water, and not just be a support structure such as polyurethane foam (i.e. not having roots grow through it).
If many components are typically available in hardware stores, have you looked at dropshipping in some way from hardware stores local to each buyer? You could ship out instructions and any exotic pieces from a central spot, plus the bulk of things from local stores?
1. This may be true with aquaculture, but in backyard-sized aquaponics, where you're not trying to breed fish, I feel there's really not that much labor involved. And the feed not only feeds the fish, it's later re-used as fertilizer for plants. If you account for both fish and plant production, you can definitely save money.
2. Maintenance time is minimal: I spent 15 minutes a day on my initial prototype, and that was mostly to feed the fish and gather the harvest, once it got going. Maintenance costs are really minimal: fish feed and seeds come out to maybe $20-30 annually.
3. I've never had a problem with mold, since the water always drains (after flooding). There is always the chance that you'll get some kind of pest or disease on your fish/plants, I've had those pests but companion planting can minimize that risk (something I'll help my customers with).
I have a pair of pet terrapins. Has anyone tried aquaponics with terrapins? They produce a lot more waste than fish. Perhaps that'll allow for more land-mass for growing?
I don't know anything about terrapins in particular, but turtles in general carry a ton of potentially dangerous diseases. In many states, turtles are outlawed as pets because their digestive systems are so geared towards incubating bacterial pathogens.
Do you mean the initial set up, or the ongoing maintenance?
Edit: I don't have an exact answer for you, but assuming you can get the system set up for less than $350 (either yourself, or by hiring an installer), that statement is true.
Also, the maintenance time is similar to what you would spend going to the store to buy the plants/fish.
However much the store you buy it from sells it for. Stores don't sell at the cost of raw materials, so the argument you can discount the cost of labour (and the cost of processing, transport and storage for that matter) doesn't really make much sense.
1) I understand buying off the shelf parts for your prototype. But spending hundreds of dollars to be shipped parts I could have bought myself is just adding more middle-men into the supply chain. At this point, just sell the parts list and plans for $20. And when you have built parts with ease of assembly in mind, so this is 5x easier than DIY with parts from home depot... THEN sell the kit.
2) You need to share data of how much water is needed on an ongoing basis, in different climates. People in Arizona with limited water supplies might not have the same resources to put in, for example.
3) You need to talk specifically about what plants work well, what the yields are,in different climates and growing zones, and recommend planting strategies for different locations.