Public Greenhouse aquaponics system proposal.

[James Keller]

So here is my sketchup for a system I've designed.  Background: There is a new vertical greenhouse that will be built in downtown Jackson, WY.  It will be on a 4500 sq ft plot, and go up 3 stories.  (verticalharvest.org)  The public will be allowed access to the first floor, and the top 2 floors are going to be used to grow hydroponic vegetables.  

My idea is to get an aquaponic system in the greenhouse for public education and to build interest in aquaponics.  

I would propose that they set aside roughly a 10' by 10' space for this project.  My design has a few unique factors, first is the L shaped fish tank in the foreground, which will house native trout, and be set up to mimic the trout's natural habitat.  Also, I chose to separate the grow beds into 3 different types of bed (flood and drain on the left, constant flood in the middle and a float bed on the right).  

The initial issue I foresee is how to keep this water cold enough for the fish - are there water chillers out there that could cool the roughly 300 gallon fish tank?  Also, would the vegetable plants dislike 45 or colder water temps?  I know these trout need highly oxegenated water, but I haven't built any kind of aeration into this system yet.  

I have no idea if they will even look at this idea, but I think it will be worth at least nailing down a design and then attempting to present it to the people who are building this greenhouse.  I designed this fairly quickly today, so any comments on this design would be welcome!  

[James Keller]

Jim - quick sketchup of the idea you proposed.  Thoughts?

[Jim Troyer]

Hey James!

You should be able to click to enlarge this (very) quick drawing.

I said "splashy riffle"; your drawing with the single drop of a waterfall into a tank will not add the quantity of DO your fish will desire.   Go look at a trout stream, observe the fish behavior, flip some rocks and look at the bugs too...  Trout tend to hang just below a splashy riffle (a long section of inclined stream filled with partially exposed river rocks) because it has lots of oxygen and the insects that live in the rocks get washed down right into their bellies.  If you set up the riffle to enter the fish tank below the water level a few inches, the trout will swim up into the riffle to pick for bugs, etc. which would be fun to watch. 

The bio filter should be after the fish tank and before the grow bed to clean the solids to keep the roots clean.  there are lots of choices to filter the water, I suggest making a careful choice as this will be the main maintenance point on the system.  Your chiller should go in there somewhere too. I also suggest an auto water level device possibly in the sump area.  Don't worry too much about things like chlorinated "city", there are plenty of microbes to go around once this system gets seasoned ...

Keep your grow beds about 2' wide, I added one you can't access in my drawing, you don't want this to happen unless they are raft beds you can put in at one end and pull out at the other after the produce is full grown.  Growing above the fish saves lots of space and they don't mind.

good luck

[TCLynx]

I agree that tilapia are over rated unless you already happen to be in a tropical location or have free heat for your greenhouse.  Even in steamy inland central FL, I would have to heat in the winter just to keep the tilapia alive let alone growing.

For my purposes I'm really happy with channel catfish and bluegill that happen to be native and easily available locally.

So if trout are a local viable option, go for it, there are many people who do trout in aquaponics (just not where I live.)

I like the stream idea.  I might have to do something like that eventually for one of my systems (well I suppose I have for my duck system.)

[Chris Carr]

Here is an idea for improving the aesthetics of the fish tank by having rocks in the bottom. Not recommended for your home systems because it is a compromise in solids removal efficiency but in a public education setting I could see where visually appealing displays can be worth the trade off.

The idea here is to elevate a non-leeching grate material of some sort such as "egg crate" light fixture coverings on bricks/blocks/whatever. Then placing rocks ontop of this, allowing for space for solids to fairly easily fall through to the bottom. The rocks shouldn't completely cover the fact there is a grate underneath, but find a happy trade off. 

A SLO drain can then (hopefully) be able to draw the solids across the bottom of the tank under the rocks. Directing some of the current under the rocks on the opposite side of the tank should help with moving the solids and prevent deadzones.

[Mark Berger]

Hi. The problem with growing trout for Aquaponics is that the trout need cool waters but the bacteria need warm waters (at least 60F). I think if you built the system above, the fish would quickly die in their ammonia due to a lack of beneficial bacteria to break down the fish waste. Has anyone successfully used trout in AP?

[James Keller]

Hi Mark - there is a group on this website dedicated to trout growing, and it looks like there are a few that have had success with trout even at high (70+) water temps.  Also, going to have to ask my friend who is a freshwater biologist, but my guess is there are different types of nitrifying bacteria strains that are resistant to cold water (if I choose to go the cold-water route).  I plan to introduce rocks from local streams that will be covered in this type of bacteria that can last a wyoming winter.  We shall see, still working on a design, and if it's rejected by the greenhouse people, I may just have to build it in my basement.  Also, as of right now, I've got about 20 happy trout fry that are living in my small system.  I caught them with a minnow catcher in a stream behind my house.  The system is about a month old and is already producing nitrates.  I would guess the temp is in the 65 to 70 degree range.  Below is my latest design.  Thoughts?

[Mark Berger]

James,

That's interesting news. I live in Pittsburgh and have a small indoor AP system with goldfish, currently. I want to build an outdoor greenhouse in the Fall and the prospect of using trout would certainly give me a greater temperature cushion during the winter. If there are nitrifying bacteria strains that thrive at around 50 degrees with trout or other local fish species (perch?) that would be awesome! Maybe I will join the trout group...

Mark

[TCLynx]

Oh plenty of people grow trout in AP, the trick is you need plenty of filtration to support the bacteria colony since they are not as efficient in cold water.  Following sane backyard stocking recommendations is usually all you need to do to have enough filtration.  Add lots of extra aeration and harvest fish before water gets too warm in summer.

[Mark Berger]

James,

Your design looks nice. A fewquestions: do you plan to grow tomatoes per the drawing? Won't the tomato plant need much warmer water than what the trout will like? Also, I did not see any structural support for the system. While very space efficient, I am concerned that your grow beds may buckle without enough support. The grow bed will employ what type of aquaponics? Flood and drain or just continuous flow?

Finally, how did you create the 3d mockup? I would like to make one for my greenhouse design and show it to you.

Mark

[TCLynx]

for growing trout, I expect one would want to stick with mostly cool weather crops.

[Jim Troyer]

That looks pretty good James! Keep the faith and post pictures, we like pictures...

Jim

[Bob Campbell]

To inspire others I think it would be better to create a simple one pump system that uses common materials and technology available from local stores.  I'd also suggest using native fish and easy to grow green leafy vegetables to avoid sophisticated and costly environmental controls.  This way the public will see something they could possibly build and maintain for themselves.

Once a person gets hooked then you can lead them further down the road and into the realm of artificial environments, computer controlled automation, water chillers and high tech water analysis.  (evil grin)

James Keller said:

Jim - thanks for the ideas!  I'd love to see pics of your set up and maybe start adding these ideas into a design.  

Sure don't want to give up on the trout idea, especially if it will further inspire folks to start looking into AP for themselves!

JK