Aquaponics - Yabby stocking density

I've been thinking about stocking density, and it isn't even close to the holiday season.

I've had a clutch of baby yabbies (freshwater crayfish like things) drop from their mother, and for the last week or two I've been watching their behaviour through the glass of their small aquarium.

They spend most of their time running the boundary and bumping into each other for a quick fight, then moving on.

The result of all this watching is that I've had an idea.

The popular numbers I hear for yabby stocking density are that you need one square metre of lake per adult yabby if you want to farm them to eat (and have them grow to a decent size), but I think that might not necessarily be the case. I think that perhaps you need a linear distance of boundary per yabby rather than an area.

I have a feeling that in a lake, the yabbies might also run the boundary, bump into each other, and fight for a bit before moving on. This would mean that a large normal shaped lake might hold less yabbies than a long thin lake that took up the same area. I'm trying to stop them fighting and to give them the illusion of having a decent patch of lake to call their own, so maybe, the longer the boundary, the more yabbies you can keep.

Maybe.

If this turns out to be true, a long thin lake with a series of baffles might prove to be the better bet.

Or not.

Who knows.








If it works I hope it makes a stack of yabby farmers a stack of money, or helps someone who depends on their yabby farm to eat eat a bit more, or perhaps it could help someone like me to grow some yabbies in their aquaponics system.

Who knows.



120 things in 20 years doesn't know.

Making smoked foods - Luxury Cut Ribs

I have a hot tip for making ribs.

It's very simple, but it always pleases.

I call it Luxury Cut or sometimes Lux Cut.

All that's required is just before serving, you remove every second rib bone, so that the ones on either side get double their share of meat.

Total luxury.

Ask your butcher to do it for you. Tell them to just throw the removed bare bones onto the scales as well so you still pay the correct amount. If you do, they probably wont charge you any more for the preparation time. Turn the bones into stock or whatever. Always go to your butcher during non-peak times.

I promise you will never go back (not to the butcher, you'll go back to the butcher. Just not to normal ribs)

And sorry to any Vegetarians reading.

Electronics - Breadboard multimeter adapter

For some time now I've been looking for a convenient way to probe around my breadboard with my multimeter. It can be a little tricky, because the probes are too thick to get into the little holes on the breadboard.


I had a bit of an idea today.

I came up with this...

It's a stereo headphone jack with a long length of header pin (sturdy wire used as a plug) soldered to the legs.

I added some insulation in the form of heatshrink, and...

TaDah!

The 120 Things in 20 years multimeter breadboard adapter.

Aquaponics - Fish stocking density

So...

1 fish @ 500g per 20L of filtration, or 2.5% of the media in fishmeat by volume (fish being neutrally buoyant equal water weight by volume  (1 ml of water = 1g) seems like a reasonably common stocking level.

...

So for every 20 L of growbed media (gravel, clay balls etc) you can stock 1 fish that you intend to grow out to plate size.

Plate size is considered to be 500g, and reflects what a restaurant might like to serve a customer on a plate rather than the actual size of your plate.

I dont know what size your plate is.

Although it's probably, by coincidence, roughly the same length as a "plate sized fish" wide.

Or high.

Anyway...

So a fish, that looks nice on a dinner plate, is around 30cm long, weighs around 500g, or a little over a pound,  and requires around 20L or 5 ¼ gallons of filtration or grow media to support it throughout it's life of pumping fish crud into the water.

“Stop eating so much. You don't need that much protein in one meal.” I sometimes tell myself. But I'm wrong. Fish is delicious, so I'm probably going to keep eating that much.

So you put a stack of fish into your system, and you end up waiting quite a while, then you pull them all out, and put them in the freezer.

But fresh is best.

Why don't we eat smaller fish? Fish are crazy brave when they are young, and feed like mad taking all kinds of risks to get to the food before their fellow fishies.  This means they grow quite quickly when they are young.

Trout and barramundi seem to grow to plate size in 8 months. But that might be because they are already quite grown up when you get them. Silver perch take around  two years. Or actually two summers, as they dont feed a lot during winter. Most fish varieties grow quite fast at their preferred temperature.

So if our systems need the number of fish they can support to give the vegies their best conditions to impress, why do we have so few fish for so long.

Most people stock a number of fish that their system can cope with once they have grown to plate size. But that means the system is low on nutrients for the greater part of a year, and then perhaps overloaded for a bit, then suddenly, has no nutrients for the plants at all when the fish are all harvested.

The system's resident veggies must hate it.

But what this means is that you either have to supplement your ammonia, or nitrate inputs into the system with Charlie Carp (fishy goo) or something to keep the plants happy.

So, all that stuff is true.

But its also true that we eat fish that are smaller then a plate sized trout. Sometimes a lot smaller.

In South Australia, where I happen to be, we eat Australian Herring, Gar Fish, Leather Jacket, Yellow Fin Whiting, and almost every other fish we eat can be bought or legally caught at smaller than plate size. I think even our King Gorge Whiting, considered by many as one of the greats, are legally caught at less that “plate size”.

So what's so good about plate size?

Don't answer that, it's a rhetorical question. Unless there is actually an answer...

then …

go for it.

But...

Ideally we should stock our systems with 100% of their fish meat holding capacity, and start eating the biggest of the small fish the following week.

That could get a little finicky when trying to fillet a 4cm fingerling, but perhaps there is some kind of compromise.

Silver perch take two summers to reach plate size.

Perhaps we should stock an amount of silver perch, such that after one summer, there is enough fish by weight, that we are not over stocked, but that we can start eating. They grow slowly in the colder time, but that might mean we can slowly eat some in an attempt to keep the stocking level at close to optimum, and when the next summer comes, we still have the right amount of fish, but we can start eating more, more often, until we find ourselves with one last megafish, still capable of running the system.

Obviously rather than one mega fish, it would be better to buy more fry at a time when the system could afford ...say... 50 new fish, if there was one less big one in the system.

That should be the trigger for buying new fish.

After working out how many fish such a program would require to restock, approximate the big fish equivalent to the number of new fry, and restock when eating the big fish would allow enough filtration media, to buy a new batch of small fish.

This might seem obvious to some, but it doesn't seem to be normal practice.

Given the price of decent quality, ethically raised, organic, un-polluted, un-heavy metalled, fish, and the feed conversion rate of around 1:1.2 (ie 1.2 kg of feed makes around 1kg of fish (insects, algae etc make up some feed, and fish do a whole lot of floating perfectly still waiting for food to wander past them, so they are fantastically efficient(some trials have shown better than a 1:1 ratio))) …

where was I...

Given all that, and the fact that you pay a bit for your new little fish (around $1.80 for me) it still works out to be an exxcellent deal to eat the fish way before they are plate sized.

So...

I think I should try to work out how many fish I should buy to make this form of stocking a reality.




120 Things in 20 years needs to make a spreadsheet to work out a better aquaponics fish stocking density plan. Or just take a bit of an educated guess.

Fire - Ethanol potato cooker

I was thinking about my Murray River epic adventure, and thought I might need a small emergency stove for when I find myself in a storm, or otherwise unable to make a fire. The difference between being miserable and content often boils down to a hot meal.

So I thought I'd make a ethanol stove. There are a few on the market, and they work by boiling the ethanol within a small chamber with holes around the top. The ethanol turns to a gas, exits at the holes, and burns like a nice gas stove. Lots of heat, light weight, and perfect for what I need.

There are quite a few examples of home made versions on the net, so after quite a bit of research, I thought I'd have a go.

I failed.

I found it impossible to squeeze two halves of a drink can that were the same diameter over each other.

Stupid physics.

So I thought I'd convert my failed project into a potato cooker.

It looked a little something like this...

I started with a can.

I poked some holes around the near top of it with a drawing pin.

I cut the top off with a box knife.

The best way to do this is to lightly score it, round and around, until you gently wear through.

I didn't do that, and I nearly cut all my fingers off one after the other in a series of ever more lucky near misadventures.

Lucky.

To cut the next bit, I originally set the can upright with the blade held at the correct height by placing it in page 321 of Stephen Hawking's book "God created the integers" which was exciting, because I finally found a use for it.

It didn't work as well as youtube told me it would.

Neither did the box knife without Steven Hawkings' help.

Eventually I used scissors. 

This pic is me cutting the planed base that the top was meant to firmly slide over.

I threw that bit away in the end, and used a potato instead.

I cut a strip from the can, and made a cut first half way through one end, and then half way through the other side of the other end.

Then used the opposing slots to make this inner sleeve.

I also cut a little v in it to allow the flow of fuel.

I sat the inner sleeve inside the outer, top bit with the holes in it.

I sliced a potato top and bottom to make a nice stable base, rested it over the top, and gently pressed it down onto the device until it was firmly stuck in place.

It looked like this and appeared to make a pretty good seal.

I added fuel up to the holes, and lit it.

At first the inner section burns and heats up the fuel between the sleeve and the outer section.

At this stage you just leave it alone for a few seconds until it warms up.

Quite suddenly and with a pleasant pop reminiscent of lighting a gas stove, the fuel turns to steam and the burner ignites at the holes.

Total surprise. 

The thing actually works. 

I quickly found a pot, and put one metric cup (250ml) of cold tap water on the heat.

As soon as you do this it snuffs the centre section, but because the holes are down a bit from the top, they continue on perfectly. 

I had a proper boil at around 5 minutes, and a slight simmer at just shy of four minutes.

Much better than I expected. This was a total success.

The entire project from the time I looked at the soft drink can to the time I could make a cup of tea was around an hour and a half, but most of that was attempting to make it without the potato. I think I could knock one of these up and have water boiled in 10 minutes with nothing but a drawing pin and pair of scissors.

Way cool. Thanks to everyone on the net that did stuff like this and gave me all your tips. My only contribution was the potato.

120 Things in 20 years - Ethanol stove - Potato cooker. Boiling water! Yum!

Thinking - Universal Theory

First let me just make a disclaimer.*

There's a stack of stuff that's wrong with the universe, but rather than tackle all that stuff, I'm just going to try to describe how it got into this state in the first place.

At least to my satisfaction.

Actually what I really want to do is see if I can describe it to my satisfaction.

Just as an exercise.

I have lots of missing bits to my theory, but I don't like all the stuff in current theories that pulls magic numbers out of hats.

And things like gravity suddenly getting repulsive at long distances. Gravity is a gentle, sensitive thing. But you don't want to get on it's wrong side by claiming it's repulsive at a distance. If you're going to say it, say it to it's face.

And all that dark matter to explain why the universe is still expanding, when according to someone's calculator, it should no longer be expanding.

So...

I'm going to try to picture a model of the universe that has none of that stuff, and still makes sense. My real aim is to test a new plausibility function of something I call the Invention Engine, but a new theory of the universe, and/or Nobel prize for physics always looks good on the resume, especially when there is nothing else on my resume.

To start with, I thought about the stuff I was thinking about when I thought I had a pretty good grasp of gravity, but proved myself wrong. That was a few days ago. It looked like this as described in a previous post called "Thinking - Gravity" and basically led me to the conclusion that, not only did I not really understand gravity, but I might never understand it.

But gravity is very interestingly odd.

That much is certain.

So ...

The one thing I really like about the universe, perhaps the only thing, is the chaos, and it's a good thing, because I'm going to need it. Not chaos like in chaos theory. Well actually it's the same stuff, but just... mess. I'm also going to need a lot of extremely sophisticated mathematics. But there's no Nobel prize for mathematics because some mathematician helped Mrs Nobel cheat on Mr Nobel or something* It doesn't really matter, but I'll ignore the mathematical proof for now.

That and I can barely count.

But mostly because there's no Nobel prize.

So we need a universe that looks like ours, but without all the problems associated with those things I mentioned earlier.

Picture a big bang**.

Any big bang will do.

Notice how all the stuff hasn't blown out from the middle to the same distance.

That's normal.

Also notice that we cant see all of the tiny detail.

It's the entire universe after all, so we are probably going to need at least a second sheet of paper.

But for the time being, lets just concentrate on a little bit of it.

Bit "A"




Bit "A" isn't a special bit, it's just a bit. There are bits further out than it, and there are bits less far out.

If we zoom in on bit "A" we would find it would be made up of lots of smaller stuff.

Lots and lots.

And lots.

All flinging out roughly from some central point. Well, that's what you might think but I don't think scientists like central points.

But I do.


Anyway, some of it has glubbed together into lumpy bits, some other stuff is glowing in the dark.

Yet other stuff is on fire, and some has given up on the entire process and has wandered off course a bit. Perhaps it was caught up in a local little bang. Perhaps it was influenced by another thing's gravity as the really big other thing rushed past. Perhaps it left its hand brake off and it simply rolled away.

Who knows.

But lot's of it is doing it's own thing.

See the stuff in point "A" doing it's own thing?

What a mess.

See that little bit at point "B".

See it doing it's own thing?

What a mess.

But lets have a closer look at point "B".

Point "B" is also made up of a stack of smaller stuff, but a lot of it is arcing a bit to the left. Perhaps it's being influenced by all the stuff that didn't go out as far.

Point "B" was full of stuff that was not going straight up (I say up, but there is no up. Only out or in, or a bit to the side) Point "B's" stuff had it's course slightly altered by some stupid thing exploding, then a big thing went past a bit to it's left.

All the stuff that looks like this.

It turns out a lot of the stuff around point "B" is on an arc that's heading roughly along the line I've drawn.

Which is lucky, because otherwise my drawing would have been wasted.

But my point is that point "B's" Stuff isn't heading straight out any more, it's on an arc, and might eventually fall back towards the centre.

I don't care if it does, because I don't believe the universe is expanding.  Or at least I'm not sure if it is. I don't think we can ever know.

Actually I do, but ...

I believe the known universe is expanding.

Not the universe.

I think the universe might be doing exactly what it should be doing if not for the magic numbers, dark matter, and repulsive gravity.

Bit's of it are collapsing in on themselves as we speak. At least I hope they are. Because then I'll get a Nobel prize, and perhaps more importantly, nothing odd has to happen any more.

Point "B" on the other hand, is racing back into annihilation as well, but that turns out to perhaps not be the contradiction that it might seem.

At one point, point "B" went through the top of it's arc at point "C".

Then it started racing home.

Now it's at point "D".

Strictly speaking, that big black shadow on the bottom of my photos is part of the universe, but it's not important at the moment.




Part of looking at my perfectly flat billiard table valley in that previous post, forced me to try to picture some stuff I wasn't familiar with. I also don't understand what the stuff from point "B" is going through, so this looks like it might be an excellent time to employ the same methods.

If a car is driving at 10 kph, and another car is travelling at 100 kph, regardless of which car you are in,  as long as you cant see the road or any other fixed point, you see that you are moving away from the other car.

You might be moving in the direction of the other car but you cant tell if there is nothing to compare your movement against.

You are moving away from the other car.

Even if you are in the slow car chasing the other car, it's moving away from you, and so as far as you know, you are moving away from it.

Rather than driving, if we were to drop cars, say... from an invisible car dispenser, we would see a similar result.

Lets time our drops so that when the first car is falling at 100kph, and the second dropped car is falling at 10kph, we stop and take a look.

from any seat, as long as you couldn't see the car dispenser or anything else, you would experience the cars moving away from each other.

If we zoom all the way in (say to galaxy sized objects) to a few objects at point "D" where the objects have passed through the top of their arc, and are heading back, we see the objects are experiencing something similar to our car's passengers.

All objects at point "D" will see all other objects at point "D" falling away from them.

Pictured here, point "E" might be falling at say 100 Kazillion kph, and the object at point "F" might only be falling at 10 Kazillion kph.

Anyone standing on either object, would experience the other object moving away from them at 90 Kazillion kph.

Even if two objects were very close to each other (like the two also pictured next to each other in the centre), they would appear to be travelling slightly away from each other, at lets say... 3.2 kazillion kph, because if the trajectories are even slightly different they will be travelling at different speeds****.

According to lots of scientists, the universe needs to weigh*** up to ten times more than it does, otherwise it would be collapsing on itself. I think this is because you need a certain amount of momentum to overcome collapse. Like you need a certain amount of momentum to overcome gravity and stay in orbit. But we can tell the universe is expanding. We just don't like it because it isn't heavy*** enough.

Not only is it expanding, but the further stuff is away from us, the faster it's moving away from us.

When you drop stuff on earth, it accelerates away from where you drop it at 9.8m/second/second.

I have no idea how fast galaxies fall when you drop them.

And that's basically it.

What if we see a tiny bit, of a tiny bit, of the smallest fraction of a section of the universe. Just some of the objects from the point "B", that are currently in a free fall to annihilation in what may well prove to be big bang number 2, (or any other meaningless and forgettable number).

Those objects within the observable universe are all racing away from each other, not toward any obvious (to the math-less observer) point, just away from each other.

The further you are away from  any given object, the faster it appears to be moving away from you.

Things tend not to expand and then collapse along exactly the same lines. In fact things tend to collapse a bit more like a whirl pool where for reasons of chaos and mess, a bit goes into orbit rather than perfectly back the way it came. So arcs, rather than straight lines.

And there's no need for any missing matter or repulsive gravity.

I'm personally quite comfortable with that explanation, but that's probably because I have no mathematics skills.

As for this theory's merit or otherwise....

I have no idea.

But it does beg the question, "What would a hole... a perfectly straight hole... a perfectly straight hole in gravity infested space ...curved space... look like, and where would a ball roll if thrown onto an imaginary flat billiard table valley?"

I have no idea.









120 Things in 20 years is thinking about the universe, and has come up with this ad hoc collection of sentences to explain it.





*Text may not reflect reality

**Actually, I suspect it will prove to be more of a big, kind of gradual... whoosh.

***mass weight whatever - I dont pretend to know this stuff.

****I know I mentioned a big heavy thing overtaking the stuff at point "B", but I'm not sure that would really happen. That was just for illustration purposes to describe some mess.  If that was to occur, there would need to be secondary smaller bangs (which I'm all for) or perhaps more of a big condensing whoosh. I dont think it would have a lot of impact either way.

Electronics - Power supply

One of the biggest problems I have with designing electronics is that I don't know anything about it, and don't know what all those little components do, so I designed this....

There are lots of bits missing, but I didn't want to go any further without getting some input from someone who knows this stuff, so I thought I'd post it any way.

It's more of a question than an answer.

"Is this something?"

The switches in the dotted line boxes are controlled by a chip.

The plan is that the capacitors would be charged either in series or parallel, so chip compares the voltage of the caps or source, and compared to the desired output voltage, it could then mix whatever capacitors it needed to achieve  the desired output voltage. With the battery (right hand side of the circuit) disconnected, the capacitors would be charged. Then the source power (left hand side) would be disconnected, the number of capacitors needed would be calculated depending on desired voltage, then they would be opened to the battery. So it might charge all the capacitors in parallel, then discharge the required number into the battery in parallel (or whatever).  This might happen a thousand times a minute or something.

I'm trying to create an "anything in, anything out" power supply that doesn't waste any power. That way I can charge my battery on my boat form a solar panel, plus a bit of wind power, and whatever else I happen to plug in.

I doubt it will work.



120 Things in 20 years dropped out of Eh?lectricity school. Can you tell?

Aquaponics - Solids removal

I'm actually a firm subscriber to the idea of leaving all solids in your aquaponics system, but I don't really have anything to inform that decision other than my thinking it. 

So we cant have that.

A healthy system can absorb a lot of fish waste and solids break down in no time. There are worms to help with that in the growbeds, but even without worms, friendly bacteria are always there to do their thing.

There's also the point that removing solids is removing hard earned nutrient from your system that the plants need.

There's also the fact that as my system stands now, I have a nice feeling that I'm working comfortably within natures guidelines and margins for error.

But enough of the sensible reasons for not messing about with solids removal. I'm going to have a go at it.

There are a few experiments from my recent past that I can call on. One is the swirl filter and it's followup, the self cleaning swirl filter. The self cleaning swirl filter was designed to separate solids, but keep them in the system, and I encourage you to click on the "self cleaning" link if you feel you might enjoy watching a video of fish poo swirling and settling. The reason I made it was to gain a source of clean water for my NFT (Nutrient film technique) pipes, but it might prove useful in this current endeavour.

I might also need a bit of electronics.

And an invention engine.

And a bit of a mental shift. I think I need to focus on water removal or recovery rather than solids removal. I need to get the water solids mix dryer and dryer.

Currently my plan looks a bit like this...

Step 1. Split the solids from the majority of the water flow using one of my self cleaning swirl filters. I suspect I'll be able to take out 90% of the water at this stage. It look like I might be able to do this stem more than once to get even more water out.

Step 2. Further separate the solids using gentle flow of the remaining water over or through a mechanical filter. Apparently, this will take the form of a conveyor belt sieve that slowly or perhaps intermittently eases solids from a water bath. At least that's what the invention engine seems to think. 

Step 3. Automatically convey the solids to a worm farm so I can add household veggie scraps and create high protein fish food. By returning the fish waste as fish food, I can still keep a natural eco-loop going, and continue to feel good about my system. Also, the fish really like the worms, and in winter when silver perch go off their pellet feed, it might be a good way to keep them growing.

Two things the final design will need to accomplish are that it will need to be very reliable, and that it will need to be very automated. I'll need to be able to go away for a week and ignore the system, and I'll need to create some failsafe system to make sure that I dont end up overloading the growbeds.

There is a great danger of overloading the system, because in order to have enough nutrient for the plants, I'm going to have to overstock my system with fish if I'm going to remove most of the solid waste.




120 Things in 20 years sees me cautiously optimistic about an automatic, aquaponics, solids removing, worm farm addition to my system.

Making smoked foods - Cold smoke generator

You can preserve a stack of stuff by smoking it, but I don't know how to make cold smoke. Or at least I didn't.

But this will work.

Sometimes I like to do stuff that's already been done, but without seeing how other people do it.

This is one of those times.

I used to make hot smoked chicken wings in a BBQ kettle or whatever you call such a thing in your part of the world. It's a BBQ with a large domed lid. It's like a grill with a big lid. Whatever...

I would get some heat beads (artificial coal like BBQ fuel that are about the size of a golf ball) and set 3 next to each other with a third on top. This arrangement would allow a heat of only 50 or 60 degrees c but would stay alight.

I'd soak some wood chips in water for a while and then wrap them in foil so they would be starved of air and wouldnt burn. Then Id put the foil package against the heat beads, and would be rewarded with a stack of smoke to impart all the yummyness that smoke does.

But I want to be able to make some cold smoke. I'm not sure why, but I've heard of it.

Rather than just looking up how to do it, I thought I'd invent something.

The result is this...

Picture a glass jar with a plastic lid. (I pictured a peanut butter jar)

Drill two holes in the lid and invert the device from it's native, and more normal peanut butter aspect. (turn it upside down)

Make a foil bowl and hug it into a heatproof tube set through one of the holes. It wont matter if it doesn't seal very well. (I think)

No, I';m sure. It wont matter if it doesnt seal very well.

Now add an air line from your aquaponic system's, or aquarium's air pump into the other hole in the lid.

Fill the foil bowl with wood chips, and light them so there is at least a small bit glowing, then screw on the lid, and start the air pump.

Add a plastic tube to the "cold smoke out" tube, and run that to a container with fish or whatever laid out.

This will.... should.... give an adjustable flow of cold smoke that will keep going for ages, and allow total control of your cold smoke preserved fish or whatever.

The air will come in and build (slight) pressure in the jar. The only way out, will be through the glowing wood chips.

It will work.

I'm going to try to make smoked sea salt. That way I might be able to add smoke flavour at will to whatever I want.




120 things in 20 years lovingly includes things that may well have already been done.

Aquaponics - Thinking low energy

Just for a laugh, I thought I'd run the low energy aquaponics question through the invention engine yet again.

Yet again, it spat out something surprising.

So far we've seen it cough up a zero head system, and then try to raise and lower a grow bed by pumping air under it, then releasing it. We've seen some kind of wacky stepped air lift, and a device that dumps air from a small pump all at once to make it pretend to be a big pump, but only for a brief moment. That way, we might send a big lump of air acting as a piston to carry water up a pipe. (I think I might have missed one) That last one I think has some potential, and might also apply to this next one. But this most recent one is most interesting, and it's this...

If you put air into a media filled grow bed that's also full of water, the air should displace water. If the grow bed is attached to a fish tank so that the water can breath in and out depending on the amount of air flow, we should see something a bit like a zero head flood and drain system, running on a few second burst from a decent sized air pump, once every 20 minutes or so.

You would need to turn the air on and off so the grow bed breathed in and out and changed the tide.

Easily enough done.

With a big air pump only running for a few seconds every 20 minutes or so, we might see a turnover of fish tank water comparable with a standard system.

So we put a stack of air stones into a grow bed under the gravel.

We flood the grow bed constantly, and connect it to a fish tank so water can move freely between the two.

Each time the air is turned on for a few seconds, water is displace by the air, and the water level of the grow bed rises.

The water then overflows into the fish tank.

The air stops, and the water fish tank water flows back until the two are back to the same level.

Repeat as required to turn over the fish tank water every hour.

Maybe.

Aquaponics - Powerhead zero head test

The absurdly low energy aquaponics system I've been working on, will probably use a power head to shift water between a fish tank, and a constant flood grow bed, both kept at the same water level so that the pump can run at it's most efficient.

To this end, I put a powerhead in a 90mm pvc pipe to see what kind of flow I can expect.

It definitely looks like being viable.

With only the tiniest head, the thing moved a lot of water. With a head of more than 2 cm, almost no water flowed at all, but I'm hoping to make a zero head system so it should work fine.

It's difficult to see the flow because I cant raise the pipe very much at all without stopping the flow altogether, but there is quite a bit of water fowing over the edge.

I would guess around 2000L an hour.

The flow at zero head with the pipe submerged is a lot more than this picture with a little head to overcome.






120 Things in 20 years, Aquaponics - Powerhead zero head test. I have an ear ache.

Aquaponics - New air lift design

If you pump air down into a submerged tube, when the bubbles rise to the surface, by virtue of the fact that they take up some space, they change the average density of the water in the tube.

The result is that the new, lower density water floats, and you get water sticking up above the surrounding water.

In short, you get a pump.

This is nothing new, and even if all you do is stick some bubbles at the bottom of an aquarium and let them rise to the surface, you are seeing what has become to be known as an air lift.

Through the introduction of air into water, the bubbles cause a vertical current.

If you stick those bubbles in a tube, you create something of a pump.

An air lift in an aquarium is mainly used to create current and keep the top surface of the water moving. This top surface is exposed to the oxygen in the air, and the exposed water gains dissolved oxygen, or DO,  essential for the ongoing good times, and life, of the fish in your aquarium, or aquaponics system.

I don't have an air pump, because I run so much water through my pump, that it's not necessary. I do run a powerhead, which is a lot like a little outboard motor, that achieves the same thing, and in my case is totally unnecessary because, as mentioned, I pump so much water with my over sized pump.

An air lift, and a powerhead both move large amounts of water for a small amount of energy. My 5000L pump was 150 watts, my 5000L powerhead is only 13 watts.

The difference is the pump could lift water 5m, and the powerhead cant really lift water at all. All it can do is stir it.

An air lift can lift water, but it's a bit limited in how high it can lift it. It would be nice if an air lift could lift air to a greater height, because then we could create a really low energy aquaponics system in a conventional (grow bed above fish tank) arrangement, and still get the desired flow.

To this end, I drew this.

Normally a picture might paint a thousand words, but this is a picture of particular poor quality, so I'll need to add a few to make it paint up to around 150.

Picture a pipe with some chambers, all sealed and air tight, so whatever pressure is in there, stays in there.

If the air lift were to deliver it's water to a chamber, the water and air would separate.

If the air was then bled off from the chamber, and re-introduced under the collected, chambered water, it might be reused to create a second or third (etc) air lift.

This might mean we could lift air higher than with a normal air lift.

I have no idea if it would work, because I haven't been able to rope anyone I know who runs air in their system into trying it yet.

If I cant get anyone to test the idea, I'll have to buy an air pump.

Either way, I'll let you know if it turns out to be interesting.



120 things in 20 years, bringing you the vaguest suggestion of science in the hope that someone else will do the actual tests and see if my aquaponic, new air lift design actually works.

Aquaponics - Absurdly low energy system

I've had an idea.

It's been a while.

I keep running the problem of a low energy system through what I like to call the invention engine, and it keeps telling me to lower the difference in height between the fish tank and the grow bed. Eventually it told me to make them at the same level, and use a powerhead to just stir water from the fish tank to the grow bed.

But when I run it with the new system design, it says to drop the grow bed even lower.

Into the negative.

Which doesn't make a lot of sense until you think about moving the grow bed back up again to drain it.

When I ran that through the invention engine, it came up with floating the grow bed in and out of the fish tank.

By pumping air under it.

An air pump is inexpensive to run, and I know it's already capable of the pressure required to get air to the bottom of a tank, because a lot of people use them in exactly that way.

The thing I dont know, is if it's capable of shifting enough volume to raise the bed often enough. It will definitely raise the bed, but if it takes too long, then it's not going to be worth it. I'm guessing I'd need to raise and lower the bed at least twice per hour. Dropping it back down should be easy to make quick, so as a target to aim for, I think I'll look at raising the grow bed within half an hour. 

So if I put a grow bed on another, inverted growbed, I can fill the bottom (upside down) one slowly with a small air pump, and effectively, float the grow bed up and down rather than shift the water up and down.

As the grow bed lowers into the water, it displaces water, causing the fish tank water level to rise, and thus contribute to submerging the media to the desired level. The reverse would occur when the air was trapped and the grow bed rises. It would displace less water, so the fish tank level would drop, resulting in a quicker low tide.

The air pump can be even smaller than I first thought, because there's really no need for all that pumping to the bottom of the tank, so no need for all that pressure. That combined with the way all that stuff in the previous paragraph should work, might mean it will be an absurdly low energy use aquaponics system.

I haven't worked out the down bit, but that wont prove difficult at all. I really enjoy inventing things where the force I'm trying to overcome is used to do the overcoming, so in this case I'd like to make use of the pressure build up to release itself, but even if I cant work something out, I can always use electronics to make a valve open at the top of the cycle, dumping the air, and dropping the grow bed back down.

I might even be able to use the rush of air to do something productive.

Cooling perhaps... who knows.

It might even be possible to use the incoming water from an existing system to get a free lift, by using it to force some bubbles under a new air powered grow bed.

Or to fill the grow bed, raise it, and then distribute the water to another grow bed, creating a kind of pump.

It might also need a few guides to keep it from wearing where the grow bed would inevitably touch the fish tank.

I have a really spooky feeling I've had this idea before, and this may just be a side effect of my current lifestyle (that being sleeping in a post-op haze) or could just be because I have had the idea before. Or it could even be confirmation of the sneaking suspicion, that whenever I have an idea, what I'm really doing is simply remembering having had the idea in the future, at some point after that.

This means all the invention engine does is jogs the memory I'm yet to have had...

yet

Either way it will work.

All it would need is a grow bed media that weighs less than the water the air displaces, and it will work.

And some buckets...

I'll need some buckets.

I'll make one tomorrow.

Buckets, and media...

I'll need some media.

Sleep now.


120 Things in 20 years, For all your absurdly low energy aquaponics systems and pre-think.

Aquaponics - Ultra low power system idea

In a normal aquaponics system, you pump water up to a grow bed, and gravity brings it back to the fish tank, Sometimes you have a sump or some other stuff in the path, but generally that's how it works.


-----------

Pumps use a lot of power to overcome gravity.

Aquaponics can work well with the grow bed constantly flooded.

Saving electricity is environmentally always a good thing.

A power head or wave pump uses a little energy to move a lot of water, but cant lift water very well.

----------

Those are four important points.

A few days ago I ran the question of an ultra low energy aquaponics system through what I like to call the invention engine, and the idea seemed to be to not lift the water as high. Each time I ran it through, the water level got lower until it was zero. Some recent experiments show that for many species at least, a constant flood grow bed is a viable way of growing things aquaponically. After all, people have been growing things in deep water raft culture, where you basically fill a swimming pool with fish and float rafts that hold things like lettuce, where they happily grow until harvest time.

Just as worms have no trouble living in flood as long as the water's oxygen levels are high, a stack of plants feel the same way.

so...

If I place a fish tank next to a grow bed, fill them so they are at exactly the same level, connect them so that water enters and leaves each container from different places, and then stick a power head in the connecting pipes, we should see an effective system running on less than a half the power use of a more conventional system.

The only issue might be the restricted flow through all the media. Power heads don't create much pressure, which is why they cant move water uphill very well. But I see my water flowing very freely through my media when the siphon triggers, so I think I'm going to try it. If it works it should also be economically viable to run it from solar.

I'd really like to see more solar designs in shops.

If it doesn't work I still have a 3600LPH hour pump I can run the system with, so there is no down side for me.

The constant flood aspect isn't on trial here. We know that works. At least we know it works for many plant species. It's the power head which is the novel aspect, and the thing I will be interested in testing. It's even possible I may be able to run the system with something called an airlift using nothing but bubbles, but that's something for another post, and is only really viable if the air pump can do the job for less than the 4-6 watts I'm hoping a power head can do it for.



120 Things in 20 years, Aquaponics - Ultra low power system idea.

Aquaponics - Stake 'n beans

I cant really see why a plant like a bean needs all the space the seed packet tells me it needs.

I figure instead of giving them some kind of string or stake to climb on, I'll just give them more beans to climb on.

With this in mind, I planted fifteen bean seeds in a single plastic NFT cup a few days ago.

Fourteen have sprung to life, and are looking good. It's still early days yet, but I suspect, with a plant like a bean, they will each find enough real estate to express their beanie selves, and will probably do alright.

That's them on the left, and right now they don't look like much, but it's either going to turn into a jungle, or some kind of rotten swamp in no time.

If it works, I doubt I'll get a harvest fourteen times as much as I would have with one plant, but I should do better than the single.

At the very least, it should be interesting.

I planted one or two in each cup in the previous batch, and unfortunately didn't count how many beans we harvested. This time didn't plant any cups with just a single bean to compare outputs with my fourteen bean cup, but that's my plan for tomorrow.

I think I'll do a test with different cups with 1, 2, 4, 8, 16, and if I have enough seeds left, I'll do one with 32 bean plants all growing in the same standard, small, plastic cup. I'll measure the output from each cup, and decide which is the beast way to go.




120 Things in 20 years, bringing you free, NFT, bean science, even if you don't want it.

Electronics - DIY waterproof switch build

It's a funny thing, but of all the wacky little inventions I've come up with since starting this blog, my DIY waterproof switch is the one I'm currently most proud of.

Here's how to build one.

I spent a long time trying to figure out a nice material to make a water proof, domed button out of.

I searched all over the place for ages until I decided to make myself a drink and found this inside my soft drink bottle.

I figured it would be perfect.

It already looks a little like a button.

I cut a 20mm hole in the end cap of the 90mm PVC tube that will house the electronics package for the demand fish feeder.

I needed to create a dome shape by pre-tensioning the gasket so I started by sticking the lid under the project temporarily with some tape.

This would allow me to press the button from the other side and hold it in place.

I added a large ball bearing to introduce a dome shape, and held it in place with vice grip pliers.

And the drink I'd made earlier.

And a box marked "Adjustable head magnifying glass".

Presumably, packaging for a device used to magnify heads.

I glued it in place and drank my drink through a straw until the glue set.












I figured with the ball bearing giving pre-tension, the glue should hold the gasket in it's new bubble shape to some degree,.

And it did.

This is the finished product from the inside.

Now when I mount a small tactile switch behind it, I should be able to press it from the outside so I can keep the electronics safe in a water proofed section of PVC.


It even works (if you can call that colour selection working (I was in a hurry))....





120 things in 20 years  Electronics - DIY waterproof switch build


All button pressing by Mrs 120ThingsIn20years. 
Mrs. 120ThingsIn20years is highly skilled at pushing buttons, and in the interests of domestic harmony, this should never be attempted at home.
Only one soft drink bottle was harmed in any way during this video production.
My drink was delicious 

Electronics - Aquaponics - Demand feeder PVC mockup

I think I have a final design idea for my demand feeder. It's only a mockup, at the moment, ie: it's only the PVC parts without any electronics or bearings.

The more I learn about this electronics stuff, the more places within aquaponics I can see uses for it.

I'll do a proper one of my Build posts when I have everything in order, but this is where it's at right now.

The basic design is a 90mm pvc section to hold the electronics (seen at the back or top left).

This keeps the electronics away from the feed and any moisture in a grow house or that just might be splashed around by fish expressing joy at their new feeder.

The electronics section is coupled to a 90mm T-junction to integrate the hopper.

In this case I've used a soft drink bottle, but any sized hopper could be attached. Another option would be one of those office water cooler bottles. Clear so you can see how much feed remains.

Perhaps for ease of refill, the top of a bottle could be cut of to act as a funnel. This could be screwed into the cap allowing the user to simply upend a similar bottle full of food into the hopper funnel.

Finally, the feed is delivered via an PICAXE controlled electric motor, rotating a screw in a 55mm (I think) PVC inner pipe. This holds the front bearing (the rear bearing is the motor, and is housed within the electronics section.

I cut an outlet hole to actually deliver the feed to the fish. I set the hole at the bottom rather than just letting the feed flow out of an open end to avoid water dripping into the feed. This could turn it into a gluggy mess, and jam the system.

The final mockup looks like this.

It'll work.
























Not just Electronics - Aquaponics - Demand feeder PVC mockup -  120 Things in 20 years

Aquaponics - auto top-up water

I've had an idea.

I had my duckweed tank connected to my fish tank via a no holes siphon (a tube full of water with en end submerged in each container). This saved the day when I had a spill from my strawberry tower.

The level in the fish tank and the level in the duckweed are always kept exactly the same, so if I add water to the duckweed tank, it flows into the fish tank, until equilibrium is reached. This means the duckweed tank breathes in and out with the fish tank.

That all works well, but I would prefer to have the duckweed tank full, to add extra thermal mass to the grow house and keep temperatures more stable.

So what I thought I'd do is make a flexible hose from the bottom the duckweed tank go over to the fish tank, but instead of submerging the end, I'll add a float, and a vertical pipe. If I cut the pipe at the same height as the duckweed tank water level when the float is floating in a full fish tank, I think water should flow from the duckweed tank into the fish tank if the water of the fish tank gets too low.

I think.

Or something.

Definitely something interesting or not should happen.

I'll try it.

If it works I'll explain it better.

Aquaponics - Growing carrots idea

I'm told growing carrots can be tricky in an aquaponics grow bed. I wouldn't know, because I've never done it. But that's not going to stop me from offering tips on the subject.

From what I've read in dirt gardening, carrots need to be planted into a bed with old fertilizer. This, I'm told, is to stop them growing legs, arms, heads, and fingers, and getting top dollar on e-bay for looking like a religious figurine. Food based religious figurines make particularly good money it seems.

So, now new fertilizer, and deep garden beds. I forgot to mention deep garden beds.

I suspect the problem with aquaponics, is that there is nutrient everywhere. This is great for most things, but annoying if you want your plants tap root to grow straight down. As I understand it, you can still grow carrots, but peeling them is like doing micro-surgery because they grow all over the shop and as a result, there is no real carroty bit.

I was reading about someone struggling with this problem when I remembered the dirt garden advice I was given, and figured I might have a solution.

If the carrot takes all the nutrient from the surface, and then grows down looking for more, perhaps all we need to do is drop the nutrient rich water level as the carrot grows.

The easiest way I can think to do this, would be to grow carrots in their own grow bed, and adjust the high tide level down each week as the carrots grow by changing the length of the standpipe.

I think I'll do an experiment with two buckets. One using the new method, and a control bucket that floods and drains like my normal grow bed. If I get rich from selling the idol looking ones on ebay, I can conclude my new system is a winner for growing normal looking carrots.



If this is not an original idea, I did my best (within reason) to discover blah blah blah

Aquaponics - Self cleaning swirl filter

Some stuff is better than other stuff.

This test is more like other stuff.

But it does illustrate the kind of thing a swirl filter might do if it were designed a bit better.


The first scene shows water entering through the thick black pipe on the bottom right of screen. The water exits the pipe via an elbow that directs water to the right so that a gentle whirl pool is set up.

You can see that the solids (these are real fish solids from a sieve I put under the inlet to the grow bed) do indeed collect in the centre and once they are there, they quickly sink to the bottom. Much of the stuff that looks like its going down into the standpipe (black centre) is actually an optical illusion. 95% of that is too low to be sucked in, but just appears distorted by the lensing that occurs with the water shape at the top of the tube. In the final product, a bell would sit over the top, so that wouldn't be happening, but that's the exit pipe back to the grow bed, so that's where we want the solids to go anyway.




After the bell siphon magically appears (I must learn how to do better scene transitions), we see the siphon kick in and most of the solids get sucked in, to return to the grow bed.

I add the same solids back again after collecting them with a spoon from a sieve.

The clear plastic tube on the left is where clean water would be drawn off to feed the NFT tubes. Water only exits via that tube for a few seconds at the top of each cycle. The length of time that water flows can be varied by the flow rate allowed through the tube. If you have a flow rate that takes a lot of water, it takes longer for the siphon to kick in. The exit flow could also be adjusted by simply moving the tube down a little from the rim. I placed it high because my little bucket was never going to be deep enough, so I was trying to get the most out of what little depth I had.

All in all, I guess this test was a success, even though it didn't work as well as I would have liked.

I Think it works well enough for me to have a go at making a bigger, better one.