Aquaponic Gardening

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Hello all.  I have not done much posting, more reading.  I attended the conference, and, man, it was great to see such passion about aquaponics and sustainability in general.  I learned a lot.  To say I learned a lot would be an egregious understatement. 

 

At any rate, I have been piecing together a system now for a few months. It is media based system with a lava rock / river rock matrix.  It consists of the three halved blue plastic barrels plant beds (75 gal total volume) and one 150-200 gal stock tank that is lined with a pond liner.  That tank itself is filled with 75 gal of H20.  The tanks are drained by persnickety bell siphons (here is a major bummer because I saw Meg Stout's talk and really want to redo my current siphons...).  I am currently trying to initiate cycling.  The pH is stable at 7.4 to 7.6.  I have not tried to adjust it yet.  The system is located in my basement and will be lit by 4 LED panels.  I plan on making fresh greens primarily and fish to eat on the side. 

 

I have two major problems that I am trying to work out. The first is the flow rate of the pump and the manner in which it interacts with the bell siphons.  At the current "head" which is not really adjustable, I do not get enough flow from the pump to get all three bell siphons doing their thing.  Bell siphons seem to need a certain flow rate to make the piping "catch" and start the suction.  Two beds will go, but not three.  So...now, I guess, I might as redo the siphons.  This will require some plugging and re-drilling but that is not too onerous.  I have two pumps I can use.  The one I am using now does about 170 gallons per hour at the head it is running at.  The second will do about twice that.  The beds will fill and drain several times in an hour. 

 

What else should I consider changing now that I am considering partially dismantling things to change out the siphons? A sump?

 

I did not get a chance to talk to Mr. Sawyer about my choice of fish species which is still up in the the air.  I live in Indiana, and heat frugally, so in the winter the temperature in the basement gets down to possibly 60 degrees F and possibly lower at certain times (never below 50F though).  In the summer it probably gets to about 75 F.  I would really like to grow tilapia for their toughness, but I would REALLY like to NOT heat the water, both from a $ sustainability perspective (as a caveat, I have positioned my system so that I can easily incorporate a solar water heating system, but I have not built said water heating panel yet, and given my other projects in the pipe line, it will not get  built this fall or winter).  As such I was thinking about doing trout.  Trout with their loving of cool temps seem fine, and I do not mind increasing the aeration with an air pump...but what about the temp maxima for the Nitrosoma / Nitrobacter being 70 degrees how does one get the required nitrogen converstion? Should I suck it up and heat the water?  Having water heated to this temp WILL cause condensation in the basement and require a fan or something to dry creating even more energy demand.  

 

I look forward to hearing the various nuggets of wisdom from you all....Meg Stout! I was not planning on trying to anything outside until I saw your demonstration / talk! Now I have added another project to my list. 

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Let me clarify about the bell siphons.  The design I folllowed from BYAB called from 1'' I.D. PVC.  I think simply by virtue of the diameter alone, flow rates need to be higher to get the siphon doing its thing. I could use the larger of the two pumps I have, but I am not sure I need the beds filling and draining that frequently during an hours time.  I would guess that each tank would fill and drain at least 3 times per hour. The other thing is that, it is hard to get an "access" sheath of large enough diameter to fit around the "bell" of the bell siphon, creating a future maintenance problem.   I think by going with the 3/4'' design ala Meg I can get aroung these problems.
Were you the young gun at the conference?

The "young gun" conference?  I attended various talks between the commercial and back yard system series. 

 

I would say go for the bigger pump.

 

Have you thought about blue gill?  They are easier to please than trout which need really top notch water quality along with the good aeration.  Blue gill will also do better than channel catfish in the small tank and they won't need heating to survive your basement.

 

Even without heating the water, I recommend you get a dehumidifier to run down there to reduce the chances of mold problems developing.  This will have the effect of heating the air some down there and it will use some electricity but mold would be a far more costly problem.

Right, I had thought about blue gill too...I am still worried about slow nitrogen mineralization...I have dehumidifier on premise already.  Thanks for your input!

 

Tiliapia seem so easy to get and so tough..., those guys seem like the path of least restistance....Hmmm. 

 

I don't know, bluegill may be easier to get than you think.  You might have to drive out to a fish farm when they have some available but I get mine for like 30 cents each where as you will probably be mail ordering tilapia so once the overnight shipping is included the fish become a little more costly.

 

As to nitrogen mineralization.  People do run systems that grow trout so it must work in the lower temperatures.  You may need more grow bed per weight of fish to handle the mineralization at the cooler temperatures especially if you are feeding a fish like trout than eats really high protein feed but it can still work.

 

I suppose how much you should heat will depend on how productive you expect your system to be during the cooler months.  Keep in mind if the air temp in the room is likely to be 75 F the water temp is going to be barely above 70 and if the tank is resting on a cold concrete floor it will likely be even cooler.  Tilapia are only just getting into eating again when the water gets up to 70.  So if that is your summertime high, don't expect much since you will be heating to simply keep them alive in the winter if the air temp stays down at about 50 F.

 

Bluegill won't require heating to stay alive but if you do heat a little with them, they will appreciate it and grow faster through winter to provide more nutrients for your veggie beds.

Hmmm, maybe drain the tank and slip some 2'' foam underneath to break contact with the floor. and maybe some covering too, that would make more efficient use of any heating I add...
Yes decoupling the tank from a cold surface will help.  And a cover that will catch the condensation and let it drip back into the fish tank will greatly help against humidity problems in the house and keep the moisture in the system.  If the media beds are flood and drain, you will get quite a bit of heat exchange with the air though which will cost you in heating as long as the air temp around the system is cooler than the water temp you want.

Yeah, that is a bummer. I saw in another post (I think it was you) that you recommended to someone a constant flow set up and said that very few plants seemed to struggle under such conditions.  I really want to minimize heating requirements until such a time that I can heat the water well without using electricity so presumably, going constant flow would minimize the heat loss experienced with a flood and drain system.  My beds are made from half barrels and are 12'' deep down the center line I would think that worms in that deep a bed would struggle, I was hoping to use wigglers in the system. 

 

Keep the water well aerated and the worms will be fine even in constant flood.  They don't need air they actually breathe dissolved oxygen through their skin and they can do that just fine under water as long as there is plenty of dissolved oxygen in the water.

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