Aquaponics Duckweed direct composter

Having dried some duckweed by spreading it out on some concrete for a few days, the next stage in creating my direct composter is using my cheese press to bring it all together. My PVC cheese press has seen a few different purposes in its lifetime, but this one looks like it might be the one it retires to.

The duckweed shrunk down to a quarter of its former live self.

I found my PVC pipe with holes that was formerly a cheese press, and rinsed it thoroughly.

I filled it with the dry duckweed, and planted it into the growbed.











The day after tomorrow, Im off on an adventure to the other side of the continent, but tomorrow, which is really the day after tomorrow a far as this experiment goes, Ill check to see if the worms like their new feeder. But really Ill be somewhere else.




120 Things in 20 years is wondering if anyone is actually following this convoluted narrative.







120 Things in 20 years thinks that as far as it can tell, its made a worm motel.

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Aquaponics Direct composter duckweed drying

My system has only one fish, and Im getting a little worried about my growbeds worm population. Im not confident theres enough fish waste going into the system to feed them all.

What I thought I might try is creating a small compost bin directly in my growbed to make sure the worms have enough to eat.

I have a lot of duckweed growing in my system, and that one fish has to power the new bigger growbed, and the duckweed.

Duckweed uses quite a bit of useful nutrient so I thought I should remove some, and add it back into the system via the composter.

 I pulled out a quarter of a bucket or so of my duckweed from the system, and dumped it on some dry, sheltered concrete to dry.










I need to dry it first to kill it, because the direct composter will be a small container full of holes, sitting directly in my growbed. That means it will be damp, and the duckweed might just stay alive.

As I understand it, worms feed on the stuff that feeds on rotting vegetation so live duckweed wouldnt work so well.


120 Things in 20 years seems to be growing plants for feed to grow other plants. I think I finally developed a way to make growing vegetables as inefficient as growing beef.

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Duckweed and String Algae

The video above is one of the best for both duckweed and string algae.

String Algae may begin to grow in your system.  Its not all bad because it can be useful as a fish food, but it tends to clog the system.  If your fish dont keep it under control a small amount of salt in the water will kill the string algae.

There are many varieties of duckweed.  I have two, but one or the other will tend to prevail depending on the time of year.  Duckweed can be rinsed and used in salads and it provides good protein for your fish.    Under ideal conditions duckweed will double its volume in just a few days, but you will probably have to raise your duckweed separate from your fish because they will eat it faster than it reproduces.

Duckweed cleans the water, but it can also exclude oxygen if it grows too thick.  It prefers warm water, and seems to grow out of control when the conditions are right.  Creating the right conditions can be difficult, so I spread it around various areas and let it grow where it wants to grow. 


Good article about Duck Weed
http://www.fao.org/Ag/AGAInfo/resources/documents/DW/Dw2.htm

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Aquaponics Direct composter success

I just got back from my trip to the East coast of Australia, and was happy to find the system ticking along nicely.

Some of the dried duckweed in my direct composter looks like it might be trying to live again, but I cant tell if its greening due to life or mould.

There must have been some heavy rain while I was away, as it was soaked through.

I think Id better put a lid on it.

When I lifted it up I saw a stack of worms going to ground into the growbed, and some more hanging from the little composter.

The worms seem to like it.

It was also very easy to grab a handful of worms for the fish, so the fish seems to like it as well.

It should also be adding some nutrient back into the system, and also saving some because of the duckweed I removed, so the plant will like it as well.


All in all, I count this a complete success, and it seems like quite a good solution to my problem of only having one fish.



120 Things in 20 years thinks flying around in helicopters is a pretty good way to spend some time.

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Good Air Pump

UPDATE: 

I found this air pump that seems to be exactly what most of us would want.
The AP 100 is quiet at 45db.
It pumps 144 liters per minute at zero head pressure
And the pressure is outstanding - 181 inches of water, but they conservatively claim 11 feet! 
100 Watts is not bad either.
It even comes with a rebuild kit!
______________________________________________________________________

This General Hydroponics air pump is Extremely Quiet has a lot of pressure (84" of water) which is required for many air lift situations. 20 liters per minute is not earth shaking but its enough to air lift the water for my Earthan Beds. 

The quiet operation and psi of this little $69.00 pump really impress me.  General Hydroponics does not state in db how much noise is made, but I think it could be placed next to a living room aquarium.  The sound of the bubbles would probably be louder than the pump.

http://www.1000bulbs.com/product/95293/GROW-GH2716.html?utm_source=SmartFeedGoogleBase&utm_medium=Shopping&utm_term=GROW-GH2716&utm_content=Air+Pumps&utm_campaign=SmartFeedGoogleBaseShopping&gclid=CN7G2qO-8rsCFcVQ7AodEVIALw

General Hydroponics GH2716 - Dual Diaphragm Air Pump

www.1000bulbs.com

Shop for General hydroponics GH2716 Dual Diaphragm air pumps. Four outlets pumping 20 liters per minute. Low prices on air pumps at 1000Bulbs.com.

Another good air pump is the Hakko.  Here are the specs of the six modles they build.
Hakko25 - 21 liters per minute, 17w, 3.7 psi (32dB)
Hakko40 - 51 liters per minute, 40w, 5.5 psi (35dB)
Hakko60 - 68 liters per minute, 63w 6.7 psi (38dB)
Hakko80 - 86 liters per minute, 85w, 7.8 psi (38 dB)
Hakko100 - 105 liters per minute,116w, 6.5 psi (40dB)
Hakko120 - 121 liters per minute,126w, 7.8 psi (42dB

For large air I have used the Active Aqua 70 lpm and the Eco-Plus 7 with 200 lpm.  Both of these are very loud.  My Active Aqua 70 lpm destroyed itself in less than a year.  The Eco-Plus 7 has been in continuous use for about a year and it runs much cooler due to the larger fin size.  Eco-Plus 7 is the better pump in my opinion.   Mine uses 60 to 90 Watts even though its rated at 200W.  It also will pump to a depth of 84".

I have no experience with the Elemental O2 Commercial Air Pumps but the
571 gph/43 lpm delivers 2.47psi
951 gph/72 lpm delivers 3.48 psi from 41watts
1157 gph/87.6 lpm delivers 4.64psi


1 pound per square inch = 27.6704523 inches of water. 

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Aquaponics Duckweed

Since I moved my duckweed into its new home its growing like some kind of thing that grows a lot.

It looked like this nineteen days ago.

Then eighteen days ago I lost a lot of it because I overflowed my tank and all the duckweed went for a walk over the edge.

It looks like this today.

Its not lost on me that this is a poor comparison.

I realise they look pretty much the same, but this latest one is many layers thick in most parts. The original pic is all a single layer thick. I had no idea it could grow this way in multiple layers.





I suspect this is a dangerous thing to grow on top of a fishtank as it might choke the water. I doubt  the water will see enough oxygen. If not for the fact that I only have one fish, I think there could be trouble.

I think I might scoop all this out and do a time lapse of it growing back, but then I think I might move it into some other containers or something.


120 Things in 20 years wants some trout fingerlings.

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Aquaponics Aeration

Im planning on buying some trout in the next few days to grow in my aquaponics system, so Im thinking a bit about my oxygen levels.

Toward the end of the trout growing period you have a lot of stuff acting against your trout. Your trout are big and make a lot of waste which depletes oxygen as it breaks down, your trout are big and need lots of oxygen, and your weather is getting warmer,  and warmer water doesnt hold as much gas as colder weather does.

You can test this by opening a warm can of beer, or waiting a few years and watching what happens when the oceans stop absorbing carbon dioxide as they warm up a bit.

Anyway...

I have a tube dumping water from my growbed to my sump.

This much water.

Its not under pressure, but is simply overflowing from the growbed at that height. ie this tubes height regulates the depth of the growbed.

no pressure

The tube stopped a few inches above the water and made some nice splashing and bubbling which I thought was adding some oxygen.

Im probably quite correct in thinking that.

But then I added a tube all the way to the bottom of the tank, and pricked a few holes in the tube just after a narrowing where there was an elbow.

This sucks air into the tube via the Venturi effect.








Apparently, this is because the water experiences higher pressure at the restriction just below the elbow, but then lower pressure when the tube becomes wider again. The result of the low pressure is that it sucks in air.

Which is a little odd.

When you put holes in (or before) the bit thats actually restricted, the holes blow out water.

I know because I checked.

So the result is that oddly enough, air is drawn in and the flow of the water draws it down.

Even more oddly, is that the bubbles dont ever really come out. Some do when the water level is a little low, but these are very small, and not many.

The tube is full of bubbles all in chaos, churning around madly.

It looks like this in real life.

The bubbles enter at the top just where the clear tube starts, and they move all the way to the bottom.

Which is also odd given how gently the water is flowing.





At first I thought they were the same bubbles, but if you block the holes, they clear after a few minutes.

Interesting.

As far as I can tell the air is dissolving.

I have no idea if Im probably quite correct in thinking this.

If gas really does dissolve in water that readily and in that quantity, its no wonder fish can live in the stuff.

I think I just got re-interested in the world.

Perhaps its because I stopped taking all those opiates for my hurty ribs.



120 Things in twenty years  thinks ribs make me less thinky.


[EDIT FROM THE FUTURE - I Thought Id add a link to wikipedias entry on Venturi and now that Ive read it I dont think I have any idea what Im talking about, but what I did clearly works. Im just no longer sure why]

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