Solar hot water - Aquaponics - NFT worm

[Edit from the future - there is some additional material on NFT ]

That previous post was meant to go out 2 days ago, but I saved it as a draft instead of publishing it.

That sums up my life at the moment.

I'm in draft mode. I found one of my fish dead, on the concrete yeaterday. I'll post about it when I know a bit more about it.

But I did take the time to check the water level in my NFT test, and discovered that not only was the water very hot, but there was a worm in it.

My worm looks like he's all broken and sore, but when I gently teased him out, it tuns out he was faking.

Perhaps he's in labour.

I've always thought that those large, white, thicker sections on a worm indicated the presence of an egg. (seen here on the left in pink)

One of the dangers in always thinking something, is that it might not be true. With anything you have known all your life, there is a fair chance your older brother was the source of the information at the worm wise age of five and a half.

I'll look into it, and if it turns out it's important, I'll let you know.

But the reason this post is in solar hot water, is than on a 17c day, I'm finding my water in the NFT tube, within the grow house, is 36c. I'm pretty sure worms don't like 36c so I moved him back into the main system. There is also the danger that something like a worm could block the plumbing and cause an overflow.

I'm guessing that's a little hot for strawberry plants as well, although they seem content enough.

That's not bad from a heat collecting position though, even if it isn't so good for a strawberry or worms position.

The strange thing is, I'm collecting all this heat from a white PVC tube, that I thought would be one of the cooler sections of my grow house. It's making me rethink the way I might go about collecting some heat to make a solar hot water heater.

The other strange thing is that the air temperature in the hothouse is 29c.

I think I might have a hot house within a hothouse situation going here.

If so it might be very easy to concentrate some pretty hight temperatures, making storage of the heat a lot more compact.

NFT test

[Edit from the future - there is some additional material on NFT ]

As usual, this is one of those things that I just made in the hope that research wasn't necessary until I had failed at least once. I really don't know things like how much nutrient rich water to flow through, exactly how deep the water should be, and, well, everything else. What I do know is that you cut some holes in PVC pipes, stick plants into the holes, and pump water through the pipes.

So I started with what I know.

I cut some holes in some pipe. This will be for seed raising so I'll cut the holes close together.

I'm hoping to be able to move plants around at will to maximise the growing space I have.

If I can move plants, I can grow them densely when they are little, move them to the medium density area when required, and then to the largest spaced holes for a while before harvest.

The plan is for small plastic pots to sit so that they touch the bottom.

And a trickle of nutrient rich water will pass through the base of each plastic pot.

Because I'm still using my sad old pump, I'm a bit limited as to how much flow I can offer the NFT pipe, so I'm stating with a only a broken stream from a 4mm (external) pipe. Basically at the rate of a dripping tap.

Next I added a 90 degree bend, and a short extension with an end cap. This should allow me to adjust the depth by slightly rolling the entire pipe and bend, so that the outlet pipe sets the desired water level.

I was going to make it so that the end cap could be rotated and thus the exit pipe's height adjusted, but it was a better option to seal everything properly (I used plumbing tape for this because I might want to pull it all apart if it doesn't work), and just rotate the entire unit to adjust water depth.

Here's a hot tip I discovered.

Its possible to make a really good seal with clear plastic hose, by drilling a hole that is a bit too small to pass the pipe through.

Cut a slice off an end to make it taper to a point.

Pass it through the hole.

Then grip it with pliers and pull like mad.

With a bit of effort (the more effort required, the better the seal) you can get a very good seal.

Simply pull it all the way through until there is the desired amount of tail on the end inside.

This will be the drain hole, and emergency overflow in case of blockage.

Having said that, clear plastic tube isn't very good for aquaponics, it gets a build up of algae on the inside, and will eventually block. This is just a test, so I want everything to be removable, and I also want to be able to see water draining, but in the final version, I will use black poly pipe.

So my final product looks like this.

Water enters through the 4mm pipe to the end on the left out of frame, and runs through until it drains back into the fish tank, through the elbow, and the clear plastic tubes.

If all goes well.

Now I can pull my new strawberry seedlings from the blue barrel, and add them to the NFT pipes without disturbing them.

This top down view shows the thin black pipe that delivers water just jammed into the hole on the side of the pot, but it will eventually have its own entry hole drilled right at the very end of the pipe.

The seedlings are already showing roots peaking through the bottom of the pots, so they should be just right for transplanting into the shallow water.

In the dirt world, you would have to transplant into ever bigger pots, but I'm hoping that in aquaponics, there will be no need, as the pot really just becomes a convenient handle to move the plants around with, and less to do with how much access to nutrient they have.

Who knows. I'll let you know more as I find it out.

[Edit from the future - there is some additional material on NFT ]

Solar hot water - Aquaponics - a day in the hot house graph

This graph really speaks for itself, but I like the sound of my own typing, so I'll be adding a bit as usual.

This graph represents my attempt to do something every hour, on the hour. If you click on it, it should open up to slightly bigger version that might be a bit more readable.

If you read all the times off the top line, you'll see I'm not so good at doing stuff to a schedule.

There was also a big chunk that should have extended out to the right for another 8 hours or so, but I went to sleep. Not a lot would have happened overnight. There have been some times where I have taken readings in the middle of the night, and the readings fit within a gradual decline over night to a point where they would roughly meet up with the 8am start data. I would expect the changes to be quite straight forward and gradual as the system radiated heat.

The cells with the yellow background represent daylight. Actual daylight at this time of year is from roughly 6:30am to 6:00pm. Roughly.

The solar heater output (graphed in yellow) comes about, as a result of a 10 metre length of 4mm black poly pipe, that I have coiled, and parked near the roof. It siphons a small trickle of water from the tap input to the glass house, up through the coil, then down to the fish tank. As far as I can see, I could just add a few more to shift any amount of heat I desire down into the fish tank, or storage, to be released slowly at night. Obviously there is a limit, but that limit comes down to how hot I want the air to be. I don't really know how hot a hot house should be, so I guess that's the next thing I need to study. It's one thing to decide to work on temperature stability, but I have a feeling I might be better off knowing the temperature I'm seeking to stay stable at.

It's interesting to note how wobbly the temperatures are outside, as compared to inside. Its also interesting to note that they seem to be getting even more stable over time.

Given I'm aiming for temperature stability, that's a good thing. I might not have to do as much as I thought. I might just have to sit down for a bit and wait.

I'm not very good at waiting, but I consider myself an expert at sitting down.

On this day, the hot house didn't see full sun until 3 hours before sunset, but when it has seen sun as soon as It could, it behaved by just being a bit hotter all round.

Sitting in a hot house is very, very nice.

Aquaponics - Hot house temperature

I've always wanted my own mini-planet, or at least some sea monkeys.

The planet I found in my black soldier fly picture looks a lot like earth, and even conveniently has the equator drawn on.

I think the equator might be the power line from my house to my shed. And Europe is a tree.

But it's still convenient, and there may well be something like sea monkeys living within its watery boundaries.

And while we find ourselves on the subject of black soldier flies. What is a fly doing carrying around, what looks like, a Venus Fly Trap on its back? Goth? Emo? Is it trying to make some kind of political statement?

But this post is about my hot house and other than that photo coming from the inside of said house hot, it has little to do with anything.

My hothouse seem to be working really well. At the very least it's a really nice place to sit when its cold, but sunny. As a result I'm spending way too much time sitting. But it's very nice.

The hot house regularly gets to a tropical 33c in a wintery 12c day, and takes most of the day to bring the fish tank temperature up from an overnight 10c -12c to around 16c - 18c. 16c is when silver perch seem to spring back into life, and so have been feeding with their old summer time vigour. Today actually had an overnight low of 14c in the fish tank, and an afternoon high of 20.

I've had some discussion with people who know such stuff, and I'm told there might be some stress for the fish with such large temperature swings, but I just realised that prior to the glass house, I saw 4c - 8c overnight lows, rising to 10c - 14c in the late afternoon. That's the same size swing, but starting from a perhaps stressfully low 4c, so who knows, but it does seem like it gains 6 degrees max.

The fish don't seem to be showing signs of stress, and are feeding a lot more. But given I like solving problems, I'll just treat this as a problem, even though I'm not sure if it is. Most of these kinds of solutions prove to be useful to someone, somewhere, so even if its not an issue for me, stabilising temperatures could well help someone else. Stable temperatures will no doubt make my fishies even happier.

So that's my new problem, temperature stabilisation within an aquaponics environment.

Wish me luck.

Cheese - Temperature control 33c

Is it just me, or does everyone constantly place thermometers all over the house, probing for suitable places to make cheese?

Last year, a good friend and bee whisperer, took pity on the quality of the coffee served at our house, and gifted Mrs 120ThingsIn20Years an espresso machine.

This was an unfortunate development, because now, no matter what, we always have to have one.

But I discovered, aside from making perfect coffee,  it also makes for the perfect place to keep a small cheese making venture at 33c.

The only difficult thing about making my totally successful bovine variety of haloumi, was keeping the temperature at around 30c.

Not that it was all that difficult to do, but it was the most difficult bit among a stack of easy things.

Our (see me claim ownership) little espresso machine has a plate on top that is warm whenever it's switched on. I'm guessing its to keep cups warm. You would have to drink a lot of coffee to leave the thing switched on, and because we try to maintain sanity, we don't use it.

As a result, it's always available for cheese making.

Thanks espresso machine.

Thanks Buzzy.

Aquaponics - Hot house

A few days ago, I bought a little hothouse.

It's actually surprisingly well made, as far as the frame goes.

I have no idea how long the cover is going to last, but I'm assured it's made of UV stabilised plastic.

If the plastic gives out on me I'll recover it with a thicker, more rigid poly carbonate sheeting.

It works. It's hot in there.

It's my new office.

The shelving will come in handy, as I'm planning to add some NFT channels or something similar, to expand my growing space.

NFT or nutrient film technique usually has 1 or 2 millimetres of nutrient rich water flowing through  pipes with a series of holes cut in the top. Small pots sit in the holes. If you've ever bought a lettuce from a supermarket with roots still on, there is a fair chance it was grown hydroponically, in NFT channels.

I think I might go a little deeper, and have a little more flow to keep everything cool.

I also just discovered these tie down things in my shed that I didn't know I had. They work like luggage tags or those single use handcuffs, and I cant help thinking the way they ratchet will be extremely useful for something down the track.

They're also very useful as tie downs.

[Edit from the future - there is some additional material on NFT ]

Aquaponics - My million new friends

It seems I'm about to have a million new visitors to my garden. I hope they like me.

All the baby spinach are covered in what looks a lot like eggs.

There is some, slim chance they are something good, but I'm told by various people that they might be snail eggs, or slugs eggs. If they are slug eggs, I'm going to have to do something drastic.

I think our snails lay eggs underground, and I met a slug couple under a rock that I moved. So I'm thinking slugs, but the eggs are tiny. Perhaps 0.2 millimetre. That's a baby spinach leaf, so these things a really small.

I don't like slugs so much.

Kind of, too... sluggy.

I don't even like the name.

Slug. Needs more g's


I found this interesting looking guy that I think might be a black soldier fly. If it is I'm very happy.

Black soldier fly or BSF, are a fly that has little in common with the house fly. For one thing they don't eat. They are really just the mating and egg laying retirement, of the BSF larva that eat compost.  They don't bother people and, as far as I know, don't do any harm. They are just obsessed with compost. I know some people like that, and they tend toward the harmless end of the social spectrum as well.

BSF larva make great food for fish. If I do have some, I might try to breed some. Perhaps I already have. They might be the ones laying the eggs.

Whatever they are, there's going to be a lot of them.

I hope they're friendly.

[edit from the future - They're not friendly. My hatched bugs look like aphids]

Aquaponics - Short siphon

A bell siphon usually dumps all the water from an aquaponics grow bed. It does this by creating a siphon once the water gets to a certain level.

The cool thing about it, is that once triggered, it lifts water up and over a standpipe, and does this until the grow bed has drained. This gives us our flood and drain cycle in our grow bed.

One alternative to using a bell siphon, is to run your crow bed as constant flood. To do this all we have to do is remove the bell, and leave the water to reach the level of the standpipe, and circulate.

It seems constant flood has some advantages.

A constant flood system holds more water, so might be a bit more stable. Whenever anything changes in a system, having more water means that it tends to change more slowly. There is also probably a bit more real estate for the micro beasties to live in.

Most plants don't seem to mind so it looks like a thing worth doing on at least some grow beds if you have more than one.

I only have one, and its very stable, but my fish are getting bigger, so there might come a time when I'm running my system a bit closer to its fish holding capacity. With this in mind I'd like to maximise my system's ability to deal with the extra load.

One possible problem with constant flood, is that over time it might be more likely for areas to become stagnant. Constant flood pulls water from the top. If you are adding water to the top and taking it from the top, the water might ignore your desire to move through the system, and just take a short cut straight from the inlet to the outlet.

A system using a bell siphon drains in a fairly dramatic fashion as all the water is dumped, often a lot faster than it went in. This sucks a lot of air down into the media, and also creates a powerful surge throughout the system. The strong surge might help to distribute solids away from the water inlets, spreading them more evenly through the grow bed. A siphon pulls water from the bottom, and this might also aid in distributing nutrient evenly.

Constant flood = good
Flood and drain = good.

I hate the way the universe can do that sometimes. Make up your mind universe.

In an effort to greedily get the best of both worlds, I have changed my siphon a bit.

The small tube on the outside is an air breather pipe. It's purpose is to aid the siphon to stop in a decisive manner. If your siphon doesn't match your pump flow, there can be a condition where, at the end of the cycle when your siphon should stop, it continues to trickle out water at the same rate that the pump is pumping in. (see this post on calibrating a new bell siphon)

This means you system can be stuck on empty.

Plants and bacteria hate that.

If your plants and bacteria aren't happy, your fish are miserable.

When the water level gets down to the breather pipe, it suddenly sucks air and stops the siphon. Basically it just makes the siphon a bit more forgiving.

What this means, is that we can mount that breather pipe further up the bell, and when the water empties to that level, the siphon stops.

So now we can have a situation where the only 20% of the grow bed is drained, but it is still drained with a powerful surge, and it also still drains from the bottom. This may well provide a decent compromise.

I have a feeling plants will enjoy having their feet always wet, but their knees in flood and drain.

I'll let you know if anything terrible happens.

Aquaponics - Worms


I bought some worms and fed them to my fish.

They went nuts for them.

My worms came in a tub that said there were 70 of them inside. It also said they were from a company called Orana Inc.  The package didnt mention what kind of worms they were so I looked up their website.

Worms have web sites these days.

It turns out these people help other people who need help, and help them help me get worms. That's a lot of help, so all things being equal, and you live in Adelaide, (which you don't) buy worms from these people.

It also turns out my worms are known as red wrigglers. I bought them from a fishing tackle store as bait worms, but it looks like they may be the same worms you might add to a composting worm farm.

Someone named suggested that silver perch might not lose interest in food over winter, but instead, might just have different food requirements. I thought I'd give it a go, so bought some worms.

I did a bit of study on worms and found they can happily live in an aquaponics system. It seems, as long as there is plenty of oxygen, they can deal with being under water for ages.

A lot of people add worms to their systems, but quite a lot find that worms have moved in of their own accord, so it must be a nice place for them to live.

I added some worms to my system.

They help break down solids like roots, that are left behind when you harvest or remove a plant. They also help break down fish solids and make sure all the solids are spread throughout the grow bed rather than all gugging around the point or points where the water enters.

I added my worms in the corner opposite my core sampler, in the hope that I will find some in a core sample one day, and gain some idea of how long it took for them to get there.

It took less than 24 hours.

This isn't a picture of it taking less than 24 hours. Its a picture of the other corner.

The corner where I added the worms.

I like my core sampler.

This isn't a picture of the core sampler, but is in fact the opposite corner where I added the worms.

Its taken a few minutes after I added the worms.

I like my new worm friends.

These are some of my new worm friends.

I don't see them often, but I know they care.


Aquaponics - Pump rebuild ver 2.0

Only 26 hours after showing off my pump rebuild version 1.0 to international aquaponics legend TCLynx, my pump started screeching, then ground to a halt.

It used to look like this.

The two bits of wire coming from opposing sides support the shaft because...

1. It's a shaft from a different pump and doesn't fit

2. Because it was a loose fit, it wobbled around all over the shop and caused a great deal of wear.

So you could describe my pump as "having seen better days".

A lot better days, and a lot of better days.

Its been running for years in an aquarium, then spent a few years in a shed, then got re-deployed into my aquaponics system.

Soon after It's re-deployment, I had to buy a new impeller. The impeller is the bit that spins around and shifts the water.

A few weeks after that I had a look at it and found a lot of wear on the front bearing.

That's why I originally put the wire in place to hold the shaft from wobbling.

So as a result of all the screeching and grinding to a halt, I pulled it apart and found what may well be the thing causing all the problems. 

It's possible the shaft is no longer within original design specs due to what may be some wear.

Interestingly, there is no sign of wear on my stainless steel wire loops. Perhaps the designers never intended it to be rebuilt with wire.

The pump's shaft looks like this.

The black plastic attachment on the shaft sits at the back of the pump in recess.

An impeller fits over the shaft, and this fits into the pump.

A face plate clips over the front, and this provides the front support for the shaft.

Or should do.

Once it started wobbling, the plastic wore out within weeks.

My original repair worked, but now that the shaft is worn, I think it requires support over a larger length.

Remembering my hand made screws I made for my fishing lure eyelets, I figured I could make a sleeve to act as the front support out of yet more stainless steel wire.

I found a rivet with a slightly larger diameter shaft than the pump's shaft, and added a few coils of my stainless steel wire.

Trimmed the excess.

Leaving me with a convenient sleeve on a wire.

Then neatly installed the sleeve into the front plate using the wire to wrap around the pump, and stop it from falling out.

The project was rushed a little because I had no water flowing through the aquaponics system, but I had it finished within an hour and 15 minutes from when the pump stopped to when the water was flowing again.

I even managed to increas the flow rate from the 70LPH or so it was flowing at a few days ago as seen here...

To a new and improved 135LPH.

Not a bad result.

I have a new pump on the way, but I really need this one to last until I take delivery of it. 

It would also be nice to have this one still running so I have a backup if the new one fails at any stage.

I love wire.


Aquaponics - Core sampler

Last night I had an idea.

I thought it might be nice to be able to see inside my aquaponics system.

I thought I should build some way to take a core sample.

I started with what used to be a aquaponics media screen, and then became a cheese press. Its now a media screen again.

I then created something similar from a thinner length of PVC, and stuck a lid full of holes on the bottom, to form a cup.

This will hold my removable, and replaceable core sample.

The plan is to push the media screen into the media, empty the media from inside the screen, and then sit the core sample cup inside.

It takes a bit of work, but I found it helped to screw the media screen in a bit. It turns out, there is a lot of friction between scoria, and a PVC media screen.

As I drilled the screen down, I removed more and more of the media from inside.

Due to the curved bottom of the blue barrel, it ended up on a bit of an angle, but I think it should work just fine.

I decided to put this contraption under my water inlet so I could have a look at the state of any solids build up.

The system is a year old now so is starting to show signs of maturity. When you dig into it, there is a faint scent of rich healthy soil. Like fresh mushrooms have.


I should be able to take the core out, dump it into a bowl, and see what state the system is in.

I'm not even sure if I'll learn anything by doing this, but it was another opportunity to drill holes in PVC so I couldn't see any harm in making one.

I plan on introducing some worms to my system, so hopefully this will enable me to see where my worms are at as well.

Now all that's left to do is sit back and soak up all the excitement that only a replaceable core sampler can provide.

[edit from the future - opening my first mature core sample]

Aquaponics - The bullwinkle sequencer build

I thought I'd put all this in one place to make it easy to link to.

Some of this is covered in previous posts, but it will be easer to follow if its all wrapped into one post.

The aim here is to make a device that will transfer water from an aquaponics fish tank, or sump tank, to different grow beds in turn. This means you can avoid dry fish. A condition fish hate.

There are existing methods to do this (I've made two other versions myself), but this is the simplest and most inexpensive way I could come up with. It also looks like being very reliable, and could probably be made from scrap. 

The device works by creating a free moving but balanced tube that fills with water. There are holes in each end to let the water out, but there is a float inside that restricts the water in an interesting way. 

When the tube is empty, the float rests in the hole, and blocks it. When a pump on a timer is switched on, the tube fills until it becomes top heavy. The device then tips, and the float drops out of the hole that is now tilted up, and comes to rest on the water until the pump is turned off. The float then settles in the hole at the other end of the device, and the process is ready to repeat.

So the float in this case is used, sometimes as a thing that floats, and sometimes as a thing that sits on the bottom, and blocks a hole. I wasn't completely certain that I understood the universe in this respect but thought it should work. I testing it like this...

Then confirmed it was worth building with this proof of concept.

Which worked a bit, but the float got stuck on my professional brown tape sealing technology.

But I made a proper one. It's called a Bullwinkle sequencer, and it looks and works like this [Edit from the future - When you watch this next video, make sure you have captions turned on, there is a stack of extra info in the captions]...

To build one, you need some PVC parts. I used 90mm storm drain fittings...

You will need...

a T-junction
2 short lengths (50mm or so) of 90mm tubing to fit your T
4 end caps
a 500mm length of 90mm tubing

You will need a ping pong ball, a drill, a length of stainless steel or wood to act as the axle for the device to pivot on, and a way to cut PVC tubing. I used a hacksaw and an electric jigsaw.

I also used a stainless steel ruler, but any long thin weight with a hole for the axle to go through would work.

I cut two holes a bit smaller than a ping pong ball, and used a hole cutter saw for this as described bellow. Another way might be to drill a hole and then enlarge it with a file. It might also be possible to buy a PVC component that is an adapter for one size pipe to the size down from it. This might negate the need for cutting holes at all.

To start with, drill a hole in your T-junction from both sides as shown. 

This will be where your axle goes through. 

Another, perhaps better method might be to glue two washers where I have drilled the holes. This way you could avoid the holes and therefore avoid have a metal bar running through your T-junction. With the washers, a bar could be placed into the washers from each side to achieve the same result. The washer would act as a seat for the axle.

I've used an iron axle for this demo because I had it handy, but its probably better to use stainless or plastic or even wood to avoid contaminating the water and harming your fish unless you use the washer method mentioned above. If you used the washers, the water wouldn't come into contact with the axle at all.

I used some lids from a powdered sports drink container for the flow control caps, but normal PVC end caps would be fine.

The only reason I used these is because I had them and didn't have the end caps.

These caps control the flow out of the device, and as such, it's important to drill the correct size hole. 

I was planning on testing this with my very tired little pump that only puts out 70LPH so that is why the holes are so small. These holes represent the exit flow from the device, and need to roughly allow the flow of the same amount of water that your pump delivers.

The device is quite forgiving with different flow rates, but you still need to make these holes so that they drain water at roughly the same rate as water comes in from your pump.

For this reason, I would recommend you drill a small hole to start with, and only glue them in place after you have established they are correct. It might even be possible to make an adjustable one, but I'll talk about that a bit later.

The flow cap fits over the cap that hold the ball. 

It's important that there is enough clearance, and that the ball can seat freely in the hole in the float seat cap without hitting the flow control cap. To this end it might be useful to add another pair of spacers (a short length of 90mm PVC.

didn't bother with the spaces. but I would if I wanted to glue it all in place and not have any leaks. You actually need a spacer here to make a proper join between these same diameter parts.

I cut the holes for the ping pong ball with a hole cutting set I bought for around $7. It looks a little like this. There is a central drill bit and some different sized rings that are made of saw blade.

You clip the required sized saw to the disk attached to the central drill bit, and you are all set to cut a hole.

I can now make PVC eggs
I cut holes in each end cap so that a ping pong ball would sit neatly in them. These need to be a reasonable fit but it doesn't matter if they leak a bit. 

Any leaks just flow into your grow bed and only for a few seconds before it tips.

It might be possible to add rubber seals to stop leaks, but I wouldn't bother, even on a real world device I was intending to put into use.

PVC tubing cuts really well with a standard hacksaw, and I cut Two short sections (around 50mm long) of 90mm PVC tubing to act as joiners and spacers from the T-junction to the end caps.

The final assemble order looks like this.

50mm spacer (with the ball in it)
Float seat cap
[This is where the optional spacers would go]
Flow control cap (with seeds written on it)

The length of those spacers isn't critical, but they are needed to make the device more forgiving, and to fit the end caps to the T-Junction. When the device is flowing freely, and adding water to the grow bed, the height of the water in this tube (defined by the length of the spacers) gives rise to a condition where the water level finds its own comfort zone. It's important for your water to be comfortable. It does this by regulating it's pressure by it's height in the tube. Remember the tube is sitting on an angle once its committed to a side. If there is more water flowing in than flowing out, this makes the water level rise within the tube. This could be a bad thing because it would overflow if not for an interesting fact. 

When the water level rises, the pressure at the exit point also increases. This means that, within reason, you can vary the amount of water flowing in, and the system will cope. A higher water level in the tube, means higher pressure, and therefore higher flow from the exit through the flow control cap. This is the bit I'm most proud of. The longer the spacers, the more forgiving the device will be. You still have to match the hole in the flow control cap roughly so that it will cope with the input from your pump, but the spacers make it so that you don't have to be accurate.

The size of the hole in the float seat cap determines the maximum flow that can pass through the system. 

These holes are around 25mm but that is only because I'm using a ping pong ball as a float. 

If you needed a bigger flow, all you have to do is get a bigger float, and cut a bigger hole. It might also be possible to use a PVC fitting that reduces from one pipe size to another smaller pipe size, rather than drilling holes at all. 

I found large foam balls at a craft store, but you might find them at a fishing tackle store, or even inside a Christmas decoration if you do Christmas where you live. A child's toy ball might also work. Ask first. The last thing you want is a cranky child when you are trying to make a water diverter.

Almost anything can be used as long as it's fish safe. It doesn't really need to seal all that well because any leaks just flow into one or the other grow bed. As soon as the device tips, the float is no longer acting as a seal, so any leakage not only goes to your grow bed, but it only lasts a few seconds.

This is what it looks like from the outside.

Next we need to make one of these. This is the extension gutter, and is there to bias the weight.

This bit is also very important to have, but it doesn't need to be all that accurate. I didn't measure any of my cuts or drilling on this prototype and it all worked first time. Even without being glued together. Its actually the pressure applied by this gutter than held the entire thing in place.

When you first start the flow, the ball is sitting at the bottom, under water, held in the ball seat cap hole by water pressure from above. If the ball displaces enough weight of water, the device will get top heavy when it fills, and tip as required. If the ball is too small, and the device is on say a 45 degree  angle, water might start to flow from the hole in the flow control cap at the top end, before the device has become top heavy. If it never gets top heavy it will never work. The extension gutter holds water and creates weight in the section that is uppermost at this stage. This means that, as far as the water is concerned, the tube is always longer on the side that's in the air. All the water on the down facing end drained away ages ago, so the extra water held in the gutter creates the desired top heavy weight bias, and decisively tips the device to switch to the other grow bed.

I made my gutters quite long, because I wanted to run my Bullwinkle sequencer, so that it would only rock 20 degrees or so. I would stop it going further by placement of the gutters that would take the water to the grow beds. This would mean my very tired pump would only need to pump water to around 150mm higher than it does now.

I think that if the gutters were shorter, it would need to be allowed to tip to a greater angle to hold enough water to create the top heavy bias required. A steeper angle might mean the sequencer would have to be raised higher and the pump would need to work harder. But then again it would be shorter so who knows. 

Only a small fraction of the length of the gutter fills with water before the device tips when it's operating to the angles shown on the video. I didn't experiment with changing the gutters because it worked the way it was. 

Basically, the gutter helps to make a Bullwinkle sequencer more forgiving of different operating parameters.

The gutter was made by cutting a 500mm length of 90mm PVC down its length.

This is done so you can slide a 90mm pipe over other 90mm fittings.

Then I made two cuts in the middle about 120mm apart that went approximately half way through the PVC pipe.

I was very casual and did all this by eye, but I guess if you were building one to use for ever, you might want it to look a little neater.

I'm not so good with neat, so I'll leave that bit up to people who are.

This cut out needs to be just big enough to fit the T-junction. It would be easy to make bigger if needed.

Next, I drilled two holes at the bottom of the cuts, to allow me to get the jigsaw in.

I cut the sections out and removed them.

You could use tin snips, or perhaps even a sharp knife or scissors.

Pry apart the gutter a little and force the T-junction in. 

Make sure you have already fitted the spacers, and float seat caps. 

I left the flow control caps until last.

Keep forcing the T-Junction along the cut gutter.

Remember none of this was glued, so it doesn't really matter. I'd leave everything un-glued until it was tested. Partly I left it unglued so I could pull it apart and take photo's, and now that it's in pieces I'll just reuse the parts for something else.

Until it falls into place.

Now all that's left to do is add the axle, and the flow control caps.

I also added a stainless metal ruler when I put the axle through. 

When the device has finished it's cycle and the pump is off, the ball drops down into the float seat cap's hole. Because the ping pong ball is so light weight, the device can almost come back to a balance position. This could give rise to a condition where, say because of the way the water came in a slight angle, it might make the same side trigger twice in a row. By the addition of the ruler, the device stays where it was when the pump was switched off. Perhaps a better way would be to add a marble in a sealed tube*, or a sealed tube filled with water. This could be attached on the side or underneath running the length of the device. All that's required is that there is a weight to hold the device where it was when the pump turned off, and that weight will shift to the other side when the device tips. If the ball was heavy enough that would probably do. The ideal would be a ball that only just floated. 

Even the pig pong would be enough if you added the water right in the middle, and kept the device out of the wind.

As it is, if a bird landed on the device, or it was subjected to a strong wind, it might upset the balance.  It would correct itself, and it starts again from such a condition, but if it happened at just the right time it could make the device water the same bed twice in a row. For this reason I'd put it in a box and put a lid on it, if I was making it for real world use and cared for perfection.

Lastly, the flow control caps need to be put in place.

If it happens that the holes that seat the float are the correct size for your flow, these would not be required, but I find its always good to have a component that's easy to adjust and or replace to set your final flow. 

You could use a tap on the exits to set the exit flow rate, or you could make two holes in 2 disks and rotate them so they don't quite align to make the size of the exit hole adjustable.

It might also be of use to mount the exit hole high. This might trap some water once it was all glued in place and negate the need for the ruler or marble tube, to bias weight and hold the Bullwinkle sequencer in the position it was in when the pump stopped.

If I was making one for real use I would definitely explore that before committing to the ruler, although the marble would be pretty easy to implement. Simple is good though.

As mentioned, this Bullwinkle sequencer is designed to switch sides every time a timer turns off the pump, then turns it back on again. But it can also be used with a pump that is always on. The only difference is that you need to adjust your flow with a little more accuracy. If the flow matches the holes in a way that allows only a tiny amount more water out than is coming in, your Bullwinkle sequencer will gradually drain and eventually the float will rest in the draining hole, and it will fill with water again, and tip to the other side. The time it takes between swapping sides, is set by the time it takes for the tube to empty and thus, the time it takes for the float to block the outlet.

 It turns out that it's not as difficult to set up as you might think, and I had no trouble making it work. As long as you can adjust the flow going in, or adjust the flow coming out, its very easy to make work.

As far as I can tell, this device is an original design. 
Its my intention that this design should be freely shared with the world. 
I ask that if you make a design based on this, that you also make the improved design freely available to the world. 
That being said, feel free to make, it duplicate it, improve it, sell it and profit from it, or do whatever you wish with it. 

Also, if you make one, please let me know as I'd love to see it use. 

I would really enjoy some feedback on this one. Suggestions, critiques, derisive laughter, whatever. It's as big as my "how to" handmade fishing lures - how to get the most out of your printer. And like the fishing lure post, I feel there is a little more room in my head after getting it out. 

I hope it's useful, and thanks for reading.

*thanks for the marble idea 

[edit from the future - There is some additional material on sequencers. ]

Popular Posts