Aquaponic Gardening

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I've seen a few discussions about small AP systems and why they wouldn't work.  How could one be designed that would work?

I'm thinking something like 3 gallons fish-tank.  For a 2:1:0.5 rule of thumb, the system would need 6 gallons of grow bed, 3 gallon fish tank, and up to 1.5lb of fish.  Basically, put a full grown 1.5lb plate ready fish into a 3 gallon tank and hook it up to a 28qt storage bin for a grow bed.  The image this brings to mind seems absurd.

I remember seeing an article about pond filters.  The premise was to compute the rate that ammonia is produced by the fish (based on how much they are fed), the ammonia that is consumed by the bio-filter, and the water retention time in the bio-filter.  The target is to make sure that the bio-filter can consume ammonia at a rate at least as great as the rate the fish produce it, and that the water is retained in the bio-filter long enough for the bacteria to do it's work.  Is this basically what is needed to design a suitable system?

Dave

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Hi David,

You are absolutely right to be concerned about the stocking density etc, and that number of fish were only in the system for a very short time - they had nowhere to go and were going to be flushed away so it was a rescue intervention!  The stocking density is now down to 5 small fish and the other fish were transferred to the system we set up in Tohoku.  So now we have just a small number of fish and everything is cycled nicely and no ammonia buildup at all.  I am going to update the website for the little black system to show this... I just haven't quite got round to it yet!

I have to agree with Rob re running the numbers so much - there really is only one major rule-of-thumb that you need to think about - as long as the volume of the fish tank is being completely recirculated every hour then you are going to be doing ok. If you want a commercial system then sure, everything can be worked out to the smallest detail - but for a home system, as long as the entire volume of the fish tank is being recirculated at least once an hour, then you are going to be pretty much ok.

If you want to see more about the mathematics and the required filtration etc then I recommend taking a look at Lennard Wilson's website which has a very handy excel download that will tell you exactly how big your filtration surface needs to be:

http://www.aquaponic.com.au/consulting.htm

Good luck with your project David


David Palmer said:

I'm curious about the micro-aquaponics system.  From the article, there are 20 fish in a small tank with a 13 liter grow bed filled with lava rock (SSA of 282:1). 

* what is the volume of water in the fish tank?

* how fast is the pump?

* how many grams of food do you feed the fish each day?

From looking at the pictures, it's clear that this system does not follow the rule of making the grow bed the same volume as the fish tank.  Thus I'm concerned about the amount of bacteria the grow bed can maintain.  How long have you run it like this?  What do the water tests show for pH, ammonia, nitrites, and nitrates?

Japan Aquaponics - アクアポニックス 日本 said:

This is also another link to our wooden micro system that we currently have running in our living room - I need to update the photos showing the plants - but will do that tomorrow I think!

http://www.japan-aquaponics.com/black-micro-aquaponics-system.html


Yes, of course you are right.  :)  However, this is just me doing what I do.  I like to study things and understand it.  I did though what you said and already built my first system.  I have photos posted already and it is growing basil, although slowly.  There probably isn't enough light.

I'm using this information to build a second system.  I have a 10 gallon tank some shelves.  I've built a new grow bed but it still needs some work as it leaks.

But the short of the exercise so far is that an aquarium based AP might work with a grow bed that is no less than 1/3 of the fish tank volume. The pump should move the fish tank volume of water once every hour.  Stocking density should probably follow standard aquarium recommendations of 1 inch of slim-fish per gallon of fish tank.  Add compost worms to the grow bed to convert fish solids.  If there are any problems, then clean and change water as per normal for an aquarium.  Ff things are going well, then this is not necessary.

I started a conversation with a guy at the Oregon Food Bank about aquaponics.  He's interested in learning more.  I may be back with a lot more questions and requests for assistance in building larger AP system(s)...

Dave

Rob Nash said:

David, you are going to get really board with aquaponics when you get past all the math, and get on to the "just feed the fish twice a day" part. ...there is just not that much to it, and youre over thinking it for sure.

try to just read the aquaponic books, and not the pond, and aquarium books.

aquaponics has its own set of rules at this point, focus on the basics of design and function, and skip the math involved with bio filter capacity etc. ...build a system already!

..here i go again, barking at the neighbors before i have had my first cup of coffee.

Thanks for the update on the gold fish.  And thanks for the link!!!  That's exactly what I'm wanting.

Dave


Japan Aquaponics - アクアポニックス 日本 said:


If you want to see more about the mathematics and the required filtration etc then I recommend taking a look at Lennard Wilson's website which has a very handy excel download that will tell you exactly how big your filtration surface needs to be:

http://www.aquaponic.com.au/consulting.htm

Dr Wilson completed his PhD on aquaponics so he knows his stuff!

I have also updated the Little Black System on the website (thank you for your reminder) so you can see what it looks like now if you want!

BTW... generally, if you put up photos of your systems then people will usually be able to see what is going on more easily and will give you lots more feedback!

All the best,

Aragon

David Palmer said:

Thanks for the update on the gold fish.  And thanks for the link!!!  That's exactly what I'm wanting.

Dave


Japan Aquaponics - アクアポニックス 日本 said:


If you want to see more about the mathematics and the required filtration etc then I recommend taking a look at Lennard Wilson's website which has a very handy excel download that will tell you exactly how big your filtration surface needs to be:

http://www.aquaponic.com.au/consulting.htm

Well, this has been interesting reading.  He really pushed home the point that the grow bed size is governed by its ability to mineralization solid waste.  He provide spreadsheets to help size the media bed. 

http://www.aquaponic.com.au/backyard.htm

For a small aquarium system though, the grow bed size is much larger than the aquarium volume.

It does not seem reasonable to expect the small grow beds to handle solid wastes without eventually  going into an anaerobic process.  This unfortunately would produce toxins for the fish unless the grow beds are cleaned.  The basic solution then is to not allow solids to accumulate. 

However, he has no go information to judge how much worms might help.

Dave

Japan Aquaponics - アクアポニックス 日本 said:

Dr Wilson completed his PhD on aquaponics so he knows his stuff!

I have also updated the Little Black System on the website (thank you for your reminder) so you can see what it looks like now if you want!

David,

Red Worms or Wriggles are self-controlling to their environment.  They reproduce ever 30 days provided they have the food source.  If the population is higher than the food available they will not reproduce.  They are very prolific so that even if you add 500 to a 10 gallon bed, they will not out grow their confinement.  I have had no escapee's and they will eat any other worms that have died.  As I said I add about a 1lb to my 10 gallon grow bed that was about 300-500 small red worms, they have been growing and can be seen through out the bed.

My worm bed started with 300 and is well over flowing and can devour a weeks worth of coffee grounds and egg shell in a day or two.  Still trying to make a good compost tea but I have plenty of compost for starter pots for seedlings before moving to the grow bed.

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