Aquaponic Gardening

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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!  

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I would start with 1 trout per 10 gallons of water (not 1 trout per 10 gallons of tank capacity). So, if you have a 150 gallon tank, you will probably keep it filled with 120-130 gallons, or 12-13 trout. If all is well, you can always stock up, but consider those little trout will grow substantially over 1 year time.

Hi James,

I've talked with Penny about this project before.  If you are serious about an aquaponic element, let me know and I'll shoot her an email. . .

Nate

Hey Nate - I've chatted with Penny a few times now, but haven't been very persistent yet.  I am currently near the end of cycling up a system in my house that looks a lot like what I think could work for them, so when that's ready to show, I was going to pursue it further.  But in the meantime, an email from you would be great if you think it would help!  I'd love to get down to Laramie this fall to check out your greenhouse.

Cheers,

James

As I understand your concept drawing.. you're gravity draining the grow beds directly back to the fish tank...

Then using an SLO to take water/solids to one of the blue barrels.. which overflows to the "sump"... from which you then pump to the grow beds... (and possibly the fish tank ala ChopII)

 

Why bother??... removing the solids in such a small system isn't going to allow you to stock any more heavily... and the design just means more plumbing, more maintenance etc...

 

Why not just pump the solids directly into the gow beds... add media.. add worms.... and cut the barrels up, and use them as extra grow beds and plant space....

Stock standard media bed setup.. simple as... thousands of them working reliably all over the world...
 
James Keller said:

So after talking with some of the people that have been involved with this greenhouse, I've submitted the following schematic as the proposal for the greenhouse aquaponics system.  Hope to hear back soon!

All of this can be bought at a local store or on Amazon.  Initial cost will be about $500 and the only running cost will be the pump on 24/7.  I will be building this in my basement with grow lights as the only addition in the meantime (when my roommate moves out soon).  

Rupert - I agree about keeping it simple.  When I went to set this up in my basement, i ended up pushing the two grow beds together on the left and moving the fish tank to the right side, perpendicular to the grow beds.  I also eliminated the swirl filter and increased the size of the sump tank.  My only worry about the solids is the fact that I made the left grow bed a DWC raft system, so there isn't as much filtration with media as there could be.  In order to take some of the solids out before they get into the raft, i have the SLO draining into a plastic bucket that sits in the sump.  This bucket is sealed with a cover (a 1 1/2 inch hole was drilled out to allow the SLO pipe to dump into it), and I also drilled a bunch of holes in the side.  The water then has to pass through filters in front of the holes before it gets into the main body of water in the sump.  I am thinking I can just take this bucket out and easily clean the filters inside in order to keep the solids manageable in the system.  Again, this is my system at home, as opposed to the system that we may be able to build at the public greenhouse.  Learning as I go!  The Trout should be going in next week, so we'll see how this all works.

I hear you James... and you certainly need to remove/pre-filter the solids if you want to use a floating raft...

 

But for a "public" simple system... then why bother with a "raft" at all.... yeah, they have a novelty appeal.. and great application on a "commercial" scale...

 

But for a simple backyard system... they're not of any real benefit.. in comparison to media beds... and just add more cost and complexity....

 

Just ditch the "raft" bed idea.... and the sump/settling tank.... fill the bed with media...  and pump directly from the fish tank...

 

I'm not convinced though that the sketchup design will actually work successfully...

Assuming its roughly to scale.... then the "swirl filter"... or more particularly the water level in the filter... will be below the level of the fish tank... less than half a barrel...

The water level in the "sump"... being feed fromm the filter... will be lower than that.... less than a half barrel... probably only around 20 gallons...

You're then going to try and pump/fill a media bed... and a raft bed.... and trigger siphons... out of a 20 gal sump...???

You're have to have a very small pump.. or you'll pump the sump dry... probably before even activating the siphon in the media bed....

But regardless... with little flow through the beds... and little flow through the SLO... little flow through the filter.. and back into the sump.... and hence probably running the sump dry...

Obviously a bigger pump would give more flow.... but you couldn't guarantee that the flow would pass through the system fast enough to supply the greater pump draw from a 20 gal sump...

 

IMO... just fill both beds with media.... pump from, and drain back to the fish tank...

(You could aplways cut the barrel in half... (you probably will anyway)... and add the halves into the system as more media beds...)

 

It'll be cheaper, easier... less complicated... and grow more stuff anyway...

 

Given the cost of media and complexity of bell siphons, I'm not sure media beds are less costly or complex, but I  agree media would be the best way to go.  I'm attracted to rafts because you can look at the roots, easily move plants, and keep a production line moving , but with the right media an Ebb & Flow system will over time be the most economical. 

Heavy crushed gravel is an initially cheap media, but it makes transplanting difficult, whereas a light soft media allows plants to be inserted even more easily than a Net Pot.  Apparently pumice is not readily available to everyone, but my recent experience with it has changed my opinion of media beds. There are other options such as expanded shale or possibly lava rock that provide a similar benefit.

The complexity of a bell siphon can also be avoided by using an Ebb & Flow design rather than a Flood & Drain method.  But it is the utility cost savings that makes this a very attractive option.  Running a pump 24/7 becomes expensive and adds heavily to the cost of the product produced.  $4.00 tomatoes are hard to swallow.

RupertofOZ said:

I hear you James... and you certainly need to remove/pre-filter the solids if you want to use a floating raft...

 

But for a "public" simple system... then why bother with a "raft" at all.... yeah, they have a novelty appeal.. and great application on a "commercial" scale...

 

But for a simple backyard system... they're not of any real benefit.. in comparison to media beds... and just add more cost and complexity....

 ...

 

IMO... just fill both beds with media.... pump from, and drain back to the fish tank...

...

It'll be cheaper, easier... less complicated... and grow more stuff anyway...

 

I think there may be some confusion here.

Ebb and flow is usually the way hydroponics does it where you pump up through the bottom of a grow bed and then the beds drains back down through that same plumbing and through the pump.

While flood and drain can be either by timer and stand pipes or by siphons.  Main thing about the flood and drain is the water enters the bed through separate plumbing and location than where it re-exits the bed so flood and drain is marginally better for solids handling/water quality and you still have the choice of doing a smaller pump running constantly or a larger pump running on a timer.  Drawback being that turning a pump on/off all the time does have some added failure rate since the initial start-up of the pump is when most wear and damage happens.  So the economics becomes balancing the constant use of a smaller powered pump or the on/off use of a larger pump to flood the beds faster along with the timer and possible increase in pump repair or replacement costs.  I have found that certain pumps stand up better to constant on/off cycles better than other pumps but even small pumps that handle the on/off cycles well, eventually exhibit wear problems after a year and a half of 6 on/off cycles per hour 24/7.

Well, this morning the nitrites had dropped to near zero so I moved my 15 trout from my old small system into the large system.  (Cycle time from start to finish was 20 days since I added a lot of water from my old system to the new system, which I think definitely sped up the cycle process)  

My large system setup is currently as follows:  110 gal Fish Tank which drains to a 110 gal Sump tank (I may convert this sump tank to a fish tank/sump tank depending on how crowded the fish tank gets when they start to really grow.  The pump sits in the sump and runs continuously and pumps water first back to the fish tank (for water movement), then into the grow bed with media and the excess flows into the grow bed that is set up as a raft.  The media grow bed is an ebb and flow with an external bell siphon.  Cycle time is around 15 minutes.  Both the raft and media bed drain into the fish tank.  I chose to go with the raft in the first place for many of the reasons Bob mentioned above.  

I may eventually add another few blue barrels as constant flood media beds in the future, depending on when I can afford to buy media again!  Since trout like highly oxygenated water, I've got 2 air pumps running, one in the raft bed and one in the fish tank and sump tank.  Lighting for the raft bed will be fluorescent and the media bed will be high pressure sodium lights (2 Sun system HPS 150 lights).  Water temp is around 62 to 65 degrees (the system is in a temperature controlled room in my basement, right next to the windows for added light).  PH is in the low 6 range now.  There are a few things I would do differently, but at this point i am very happy with how the system is set up and working.  We'll see in a few months how the filtration in the sump handles the solids, but everything is easily accessible and therefore should be easy to clean.  

James

I would not bother with siphons at all. Various real world tests have proven them less productive than constant flood setups. Also they're prone to failure or at least requiring maintenance. And, they will raise or lower your water temps drastically which is especially counter productive when raising trout. Plus you don't need a sump!

I don't know what real world tests have proven siphons less productive than constant flood.  Can you share links for such examples?

I do know that some real world tests have shown constant flood to be not much less productive than the two different flood and drain methods.  The three methods side by side in a very small scale test only showed minor variations in performance between the three methods.  With constant flood perhaps providing quicker system cycle up time while the plant mostly did best in the timed flood and drain while some plants still did really well in constant flood and the general outcome of the test was that all three methods WORK.

My small system started out as a flood and drain, and then one day i decided to remove the bell siphon and let it run constant flood.  Everything did great (except the strawberries, but I think that was a bad batch anyway).  So I would have no problem running a constant flood with this external bell siphon in my large system, simply by removing the cap on the siphon or drilling a hole in the top.  However, I do like to keep the ability to "flush" the media grow bed every once in a while to make sure there aren't any "dead spots" in the grow bed.  This may not really be an issue, but it makes me happy to know that I can do it every one or two weeks.  

I would also argue that with certain plants that I directly seed into the media, that I would get a more constant germination rate with constant flood since I know right where that water level is at all times.  Any thoughts?

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