Backyard Aquaponics
A place to discuss aquaponics

Yea Rupe, I know- I was hoping so too. One of the reasons that I went public with my design is to get others interested in building a system similar to mine, then we could collaborate findings and trouble shoot problems together. There is no question that AP systems work but how well will they operate over the long run, with commercial stocking densities? What problems will you encounter over time and how often? And sometimes when sharing ideas with other people, they may come up with something that is just a little bit better than what you have- sometimes small things can make a huge impact, especially when it come to logisitics in commercial applications. My discovery of using cheap 6 mil plastic, that is common at commercial hardware stores, instead of EPDM pond liners is a huge difference in cost, especially when you have two or three dozen ponds- it may even mean the difference between getting a business off the ground or not.
Another example are the S&S gravel style systems, they are very productive, no question about it, but not sustainable over the long run from a large scale commercial point of view. For one thing the cost of all those raised bed and plumbing was very exorbant, the other one was- if you hired labor, and even if you designed driveways for electric golf carts, there was too much wasted greenhouse space and too much walking between the beds for manual harvesting- wasted space and time are literally money out of your pocket. The only exception is if you can get a large area growing something that must be manually picked, same as in regular agriculture, such as strawberries- but again the S&S design fails in infrasture costs.
That is why DWC is unbeatable from a commercial point of view- load one side, harvest the next. Conveyor style systems have proven themselves time and time again from the manufacturing of cars to the slaughtering of pigs- let the product come to you to reduce labor overhead.

I agree Angie... F&D growbed systems have a definite place in backyard food production, but aren't scalable to a large commercially viable business operation IMO...

Although "large" and "viable" may depend somewhat on an individuals perception and aspiration....

DWC is a proven, working model with "relatively" cheaper infrastructure cost /sqmtr...

As long as you can get the land at a reasonable rate... and have a market niche available...

I'll be watching your project with great interest...

As I told TCL, I still believe that gravel growbeds have a place in commerical applications but they must be bigger, at or close to ground level, with an overhead or movable water delivery system. When you make a gravel growbed like this, you can get ecomonies of scale and maintain infrastructure costs. Also you have the ability to maintain the beds with long handled tools or depending on bed design, heavy equipment and manage optimum growing area.
This growbed design is what I am using a a water pre-conditioner to my DWC and probably the biggest difference between me and UVI. They use clarifiers but these waste water and labor and I think this system component can be improved upon.
Proof will be long term use, to see how well water quality can be maintained as the solids break down with greater and greater stocking densities. This is the biggest "what if" in my system.

Jezz... great minds think alike Angie...

Recently submitted a grant proposal for a client... based exactly on that model...

Large gravel beds at ground level to grow high value crops... like tomatoes... as a pre-filter to a UVI raft system....

Along the lines of the pioneering hydroponics work of James Sholto Douglas.... a technique referred to as the "Bengal System"....

First known reference to the use of gravel substrate... along with other substrates that he trialled...

Surprised nobody has picked up on the idea before... think you might be on solid ground Angie...

I still don't see why gravel beds are so uneconomical. Sure, they are heavier and require stronger supports, but the media is dirt cheap . Plumbing is a one-time cost, and isn't that complicated.

Sure, your DWC beds are 4' wide, and your gravel beds are probably more like 3' wide. But you get higher planting densities in gravel.

Problem ...IMO... is when you scale up to multiple beds.... and large beds, much larger than normal backyard beds...

You want proof- add this up and remember this is for only 12 grow beds.
Available on-line
The Freshwater Institute Natural Gas Powered Aquaponic System - Design Manual
Growing Beds:
4' X 8' Pre-assembled root zone heating module 12 $74.03 $888.36
Set Point T'Stat 1 $97.86 $97.86
Grundfos 26-96 Circ Pump 1 $144.00 $144.00
#8 quartz river gravel (pea gravel) 20 $22.50 $450.00
8" cinder blocks 216 $0.77 $166.32
18" Paving stones 72 $5.15 $370.80
white 20 mil plastic liners 12 $27.00 $324.00
4*8'*3/4" Plywood 12 $25.49 $305.88
Pre. Tre. 2"*12'*8' 36 $13.69 $492.84
Pre. Tre. 2"*4"*8' 72 $3.99 $287.28
bed shims 12-5/4"*6"*8' $50.00

Although this is considered a commercial system, it is geared towards produce, not fish. Use commercial fish stocking densities and then see how your infrasturture costs soar.

I won't even bother telling you about the maintenance issues of mutiple beds like this and lost greenhouse space, at premium prices.

Well, that's sure an expensive design.

Are you running stocking densities higher than the 3kg per 100L of filtration?

Once I am at maximum capacity, I will be running commerical aquacultural stocking densities, based on species.

we have found that large quantities of deep (40cm) gravel growbeds are better at solids filtration than swirl & bead filter combo.

G'day Angie,
Been following your posts for a while, but the above quote now means you can count me in. Very happy to share info and findings as we go along. Am planning a very similar system to yours here in Oz. Scalable, replicable and commercial. Have made contact with Tim Mann and I am planning to visit friendlies in Hawaii in May/June (brilliant $300A return airfares atm!!) and examine their operation and system. Will take lots of pics but am technologically challenged so may need help posting them here upon the return.

We already run an organic farm in New South Wales near Canberra, but the last 7 years of drought has forced us to examine all options. Our climate also means hoop houses and solar heating will be required. We have plenty of clean water but I was looking for the most bang for my water $, and aquaponics stood out the obvious answer. I already have outlets for all the produce I grow, it's just a matter of doing it most efficiently and effectively - economically, ecologically, socially (triple bottom line).

Anyway PM me and I'll give you my contact and website details, but happy (and would prefer) to keep it all out here on the forum and in the public domain - so others may benefit from the mistakes/ learnings.

btw the half T post (star picket in Oz) suggestion from another post does work. The 5'6" ones cut in half are near perfect. We will use the gal coated ones as our soils are a little on the acid side - pH 4.5!

Cheers, mcfarm

Mcfarm, I posted my reply on my system thread. Welcome aboard.

Basically you pump water through a bio filter like bags of pvc shavings, and remove solids. Then you send that water through troughs with floating foam and net pots. Or UVI'ish model where you remove excess solids and keep all water out of sunlight and let the bacteria in the water do the bio conversion of ammonia.

There are a few more tricks if you want grow fruiting crops.