Posted by: permamonk | April 3, 2012

Aquaponics – because a closed system is a happy system

OK, so here’s the deal:

Aquaculture is a contained system of farm raised fish.  Of course, anyone that has ever kept even the smallest fish tank (remember that gold-fish your son won at the church fall festival, and you had to secretly replace a week later with one from the pet store before said son got home from school…) knows what happens to fish water.  Even with the best filters, the water has to be changed as the fish just keep doing what God intended fish to do.  In commercial fisheries, this water can get dumped out into rivers and lakes, creating all kinds of fun environmental problems. One thing that fish are reeeeaaaallly adept at producing is ammonia.

Hydroponics is a contained system of vegetable farming that grows plants in soil-less mediums, either directly in water or in aggregate that is flooded and then drained to keep the roots wet and supplied with nutrients.  In order to keep these plants healthy, fertilizers have to be constantly added to the water to keep the proper chemical balance suitable for the plants.  What plants reeeeeaaaallly love is nitrogen (the N in the NPK triumvirate).

Bacteria are fun little microscopic creatures.  They can do many, many things like help you digest your food or give you food poisoning.  What’s the difference between good bacteria and bad bacteria?  Well, at the risk of simplicity, good bacteria is simply in the right place at the right time.  Now let me introduce you to two very important bacteria for the purpose of our experiment here.  First, please say hello to Nitrosomona!  This little guy loves ammonia and converts it into nitrite.   Next up is Nitrobacter!  This industrious little fellow loves nitrite and oxidizes it to create nitrate.  Want to guess who likes nitrate?  That’s right!  Our hungry, hungry plants just love this stuff!

Have you, as an adult, ever sat down with a toddler appropriate jig-saw puzzle?  I’m talking about those toddler puzzles with pieces so large you can use them as coasters for your adult drinks.  You know, the puzzles that have a staggering six pieces?  Well, as adults, we look at these puzzles and think, “Wow! That’s easy!”  Well, industrial growers have been staring at this big ole puzzle of only six pieces for quiet some time, and instead of putting it all together, they’re chewing on the pieces because they think it’s a cracker.  Now, I don’t want to discredit these industrial farmers too much, because until only recently, I hadn’t put these pieces together either.  But after watching my first youtube video on it, I had that “Well HO-LY SH*T!” moment.  (That would be the adult maturation of our toddler “Yay!” experience.  Teacher’s call it the “Ah ha!” moment, but that seems far to reserved for the experience I had.  “Ah ha!” is something you say when you look around the door and finally catch you cat nibbling the house plants that have been growing progressively leaner over the past month.  “HO-LY SH*T” is what you say when you discover something that should change the world.)

So let’s put the pieces together.  If we have a tank for our fish (whether decorative fish or edibles), we now have a supply of ammonia concentrated water.  Feed that water into another tank with a lot of surface area for bacteria to grow and do their thing, and you wind up with nitrogen rich water.  Run that water through a growing bed of plants and the plants are fed and filter out the water, all the while reducing the amount of water loss due to evaporation or infiltration.  Now you have clean water which is run back into the fish tank.  Be sure to aerate the water and you have happy fish that will happily start the whole thing over again.

To be fair, it’s not an entirely closed system.  The biggest ingredient that you have to keep feeding into the system is just that: food.  Granted, I’ve seen some setups that produce algae in order to feed the tilapia, but I’m not up to that yet.  The other ingredient that needs to get added periodically is iron for the plants.  That aside, this is a pretty self-contained system.

To check out just how complex it can get for a “home” project, here you go:DIY Aquaponics

Needless to say, our’s won’t be anywhere near that complicated.

Tune in next time for “Best laid plans of mice and monks really need to double-check the scale of their blueprints before buying lumber…”


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