Aquaponics Design phase begin.

[Philip Vanderhoofven]

Hello all,

I'm relieved to find an online community to bounce some ideas off of. I have been thinking about aquaponics since I discovered it a year ago on a PBS special. I took notes and started searching for simple design parameters. Such as how many fish will one person eat in a year. I know there is an answer out there but really its subjective to the person. I eat fish maybe every other week so thats maybe 23lbs of fish I'd eat in a year. Anyway, I went out to Olomana Gardens in Waimanalo, Oahu for a tour and have been thinking about designing and building a small home system ever since. Here is what I have come up with so far;

 

3 - 8X2 ft growing beds 12 inches deep (lava rock growing medium)

1 - 250 gallon fish tank

up to 48 lbs of fish at any one time.

 

Here's the twist - 3 - 8X2 ft rabbit cages under the growing beds.

And another twist - Make the fish tank look like a pond by burying most of it and have the return lines from the growing beds cascade as a water fall.

 

The rest of ideas that I want to incorporate are;

 

 3X bell syphons for the flood/drain growing beds.

maybe a smaller pond up higher for duck weed and breeding the replacement talapia.

 

Any helpful ideas are welcome.

[TCLynx]

The smaller thanks only really limit the size of the fish that will comfortably grow in them but if you are not wanting to grow out channel catfish the way I do, you should be ok.  Just have the some where around 300 gallons total of tank and you should be able to keep water temperatures consistent enough.

 

As to the slightly shallow grow beds.  You will probably still be fine for most annual veggies (lufa may be an exception, I think mine have totally filled a 24 inch deep grow bed with roots but I won't know unless I really dig down to see how deep they are going.)  Just make sure you keep the drain area accessible so you can clean out roots that start to interfere with drainage around siphons or stand pipes.  12 inches deep is simply a good standard to aim for but I know people with 8 inch deep mortar tubs as grow beds and they are managing while I've found a few plants that are capable of clogging a 2' deep bed with roots.

 

Use what ya got

[Philip Vanderhoofven]

 

Thank you TCLynx for commenting. That is probably why I couldn't grasp the system volume because we were talking about it in terms of area instead of gallons.

 

I found a local aquaponics supplier in Waimanalo and I went there yesterday to check it out.

 

My design is changing due to a few factors. The main one being that the available 300 gallon fish tank is slightly bigger then the space I have available for it and it looks hugh. Even if it could fit we would have to walk around it. And there is no way to make this giant tube look anything like a pondscape. So the next size down for a fish tank is only 180 gallons. (36 fish is still more then I eat in a year). I will probably have to set up another tank next to it to keep the water level constant in the fish tank with a CHIFT PIST. Maybe the two together can look like a waterfall some how.

The 2X8 ft grow beds available are only 10 inches deep with 8 inches wet. I'm not sure how bad this is going to limit my vegetable choices. Am I stuck with growing lettuce? But these grow beds are looking great. And since only eight inches will be wet that cuts the volume down in my grow beds to 270 gallons total. Filled with black cinder medium and the volume of water required to fill it should be cut in half at 135 gallons total (45 gallons for each grow bed). Even if they all filled at the same time it would only drop my fish tank level down to 45 gallons still in the tank which is still more then a gallon of water for each fish to swim in. 

Of course this doesn't leave any room for error like if a leak sprung some where then the fish would be flopping around. Which is why I'll need that extra water tank with the CHIFT PIST set up. 

 

I cant check Dr. Lennard's model on this computer.  Thanks for the advice. Really appreciated!

 

 

[TCLynx]

hay Phillip, welcome.

There are many options.  Let me see if I can wrap my head around some numbers here.

I tend to think in volume rather than square feet so I gotta convert a few things.

Ok, so 3, 2x8 (at 12 inches deep) grow beds is about 359 gallons.  So if you flood that all at once from a 250 gallon fish tank the water level is gonna get a bit low on you, hence why the calculator recommends a bigger fish tank, And a bigger fish tank will also help with temperature stability too.  So if you were to get a fish tank that is big enough to handle at least 360 gallons of water and have some free board above it to keep the fish from jumping out, you should be ok with a simple system provided you only stock about 48 fish intended to grow out to a pound each.  (a vague rule is that it takes around 40-50% of a grow beds's volume to flood it so for a simple system doing flood and drain with no sump or other means to control water level fluctuations, your fish tank needs to have at least as much water as your total grow bed volume.)

 

Now there are other options to manage the water level fluctuations.  You might set one or two of those beds to be constant flood so they won't mess with the water level so much and have the other one or two fluctuate with a siphon.  Or you might use an indexing valve to flow the beds one at a time using a timer to turn the pump on and off.  (you can't expect siphons to sequence accurately so at some point all beds are going to flood at the same time.) 

 

You can also manage things by designing a CHOP (constant height one pump) or CHIFT PIST (constant height in fish tank pump in sump tank) system so that you would have your 250 gallon fish tank and a separate sump tank to absorb the water level fluctuations.

 

Either way, I personally like to move at lest the volume of my fish tank per hour and I often pump twice that since it can provide more aeration and even nicer water for my fish.

[Philip Vanderhoofven]

Hey Rob,

haha not the best profile pic but it was the rare time I put on a suit for Susan G. Komen fundraiser fashion show. I didnt get a kiss and thats alright as I was there to support my wife and we did quite a bit of design construction work for the event. See me any other day of the week and I'm getting dirty outside with worms and gardening ruining all my white t-shirts and basically enjoying every second of it.

 

I've spent the day going through aquaponics links and reading all the beginner guidance on this site so hopefully I dont sound too dumb when I put together questions.

Dr. Lennard's system design tool validates what I was designing but reading through some of the comments and my first real quesiton has to do with system water. Putting aside all the other criteria, plants, fish, bio-filtration, nitrification, oxygenation, mineralization, pH, ammonia levels, etc, I cant seem to wrap my head around the basics of the volume of system water. Here is the question for the flood and drain system.

If I have a 250 gallon fish tank (Dr. Lennard recommends 317gallons) and 352 gallons of wet grow bed volume (3- 2X8 10 inches wet) how does this work???? Obveiously pumping 59 gallons per hour makes more sense then pumping 250 gallons per hour.  I'm not clear on the pump recommendations, most say 100% an hour (15 min 1000gallons per hour pump)  vrs. Dr. Lennards 20% per hour.  So the next question is wouldnt an 1000 gallon pump drain all the fish water out in that 15 min?  That just doesnt make any sense to me. How would you set up a pump requirement for a 250 gallon fish tank on a flood and drain system using a bell siphon. Or should I make each of my 3 grow beds individual with thier own bell siphon and some how sequence them so they dont all fill up and drain at the same time?

 

 

[Rob Nash]

turn and kiss the girls in the picture.