Aquaponics - Pump-less cycling

Fish-less cycling is where you breed up a colony of nitrifying bacteria in your aquaponics grow beds by adding a source of ammonia to your water as it pumps through your system. You do this because there is some risk to the fish in an immature system. Those risks are lessoned once your system is able to turn ammonia into nitrites, and then nitrates, at a rate that will allow the system to cope with the desired level of fish stocking density.

I still don't have my fish tank and sump, so I thought I might give the nitrifying bacteria a head start by just adding hardware store bought fish emulsion by sprinkling it on with a watering can.

I still don't have a watering can so I made one from an empty soft drink bottle.

I have no idea if this will work, but once I get my fish tank and sump, I should know if it has helped speed up the process of cycling the system.

Its about to rain so I'll just sprinkle it on top and let the rain do the rest.

This is the second time I have done this, and the last time the gravel remained wet for a week, so there is a chance this might work.

I'll let you know.

Animation - Bell siphon

I've decided to learn how to make animations so as to be better at communication.... And stuff.

Earlier attempts I have made were created frame by frame, but I recently nabbed a copy of Synfig Studio.

From what I've seen so far, It looks the goods. Its free to download and use and its all open source. Yet again the open source community has exceeded my expectations. All these people who contribute are truly amazing. Thank you all.

Here is my first attempt that actually worked. Depending on what I can offer, I might make animation or visual communication a "thing" because I'm sure I'll need the skills more and more, no matter what I do in the future.

The bell siphon is running with a continuous inflow of water. The siphon triggers when the standpipe fills with water. The grow bed (terracotta colour) floods and drains automatically, creating tide-like conditions for plants. The bell siphon is commonly used in aquaponics as a method to flood and drain grow beds. The water drains back into a fish tank, where a pump cycles it back to the grow bed.

A bell siphon (in yellow) triggering and draining via the standpipe (in green)

The real things looks like this from an earlier post called "Aquaponics - Glass bell siphon"

I just re-read this post and it doesn't sound like me.
But it is.
There, that's settled that.

Aquaponics - Goats really are fun

My goat broke my automatic feeder today.

I guess it tasted good, but it might have been more polite to just eat the fish feed and leave the switch alone.

And so far the only gold I have found in all that gravel was this.

It's an interesting crystalline substance that, up close,  looks like plastic gold jewellery, mixed with crushed glass.

I've never seen fools gold before.

I don't feel foolish.

Other than that, everything at the auction I went to was selling for way too much so I'll forget buying a purpose built fish tank, and go back to the original plan of buying some IBC's.

IBC's are how we humans move our ever growing numbers of litres of liquids needing transport across the world. They are generally white(ish) plastic and take the form of a cubic metre drum in a cage on a pallet.

Make sure you know what was in them before you buy them. There is a stack of toxic stuff moving around the globe in these things on any given day. Luckily, many of them carry things like soft drink syrup. Many are not food grade plastic, and its a good idea to check for cracks and flexibility as they become brittle after too long in the sun.

Aquaponics - Marron stocking density

I'd like to grow some marron but they eat each other.

One of the issues with things that use their claws to catch and kill things, is they tend to use them on each other, or their young.

Marron, for those who don't know fall into the "things with claws that walk on the ground under water" category. They also fall into the "delicious" category.

The problem is that, because they eat each other, you cant keep many in an aquaponics system. Given a choice, marron would like to be left alone and hangout and eat. The problems arise when they go looking for food, or a mate, or when the just go out for a stroll and bump into another marron also out for a stroll.

One solution is to give them plenty of hides in the form of hundreds of short lengths of PVC tubing. Which sounds like a good idea because I seem to love using PVC tubing, but I'm not sure if it solves the bumping into each other problem.

Another is to only populate one marron in each half square metre of fish tank bottom space. That would only allow 2 or 3 in a 1000 litre system, but allows each marron to back away from more aggressive marron they meet strolling around. I'm hoping for stocking densities that might allow 30 or 40 marron in my new fish tank rather than 2 or 3.

Yet another solution I have seen, was to create high rise housing that float around in a fish tank where each crustacean (yabby in this case) has its own space to stop them killing each other.  The yabby spaces where stacked on top of each other so that in a one metre deep fish tank, there might have been ten stacked on each other. These yabby buildings floated around in the current. The problem I see with this approach is that unless there is a great deal of turbulence in the water, the feed might never meet the yabbies. In the system I have seen video of, there seemed to be a great deal of wasted food that simply got filtered out of the system, and dumped.

Other than the feed issue, the marron high rise seems like the best idea. I think I'm leaning in that direction, but perhaps with a way of feeding each "building" via a tube that runs down through each marron's house, so that each marron gets a share of the food, and nobody misses out.

I'm off to buy a fish tank or two tomorrow, so I want to design a system that includes marron before I start building my new bigger aquaponics system.

My research continues.

Aquaponics - Goat

As useful as Granger was in helping me to make home made goat dung volcanic growing media, it turns out goats have no place near plants and gardens.

I thought I had him safely blocked from my small aquaponics test system, but people often think things like that when it comes to goats, and are often proven wrong.

This is what my grow bed looked like before the attack (actually this picture is older but you get the idea).

And this is the same plants now.

I walked into the back yard and saw my goat chewing a mouthful of strawberry plant, with an expression of surprise that I seemed to be upset.

I replied by turning on the hose, running around shouting, and trying to squirt him.

He seemed to think it was all great fun and promptly did what goats do when you chase them around squirting them with a hose. Head for the hills.

That's him on my roof.

Laughing at me.

My grow bed looks like this now.

I managed to save the rosemary, two strawberry plants (one with two runners forming), and some celery.

Aquaponics - Gravel


I got some 20mm blue metal road gravel, as growing media for my new, larger aquaponics grow bed.

It looks like this.

And unfortunately it needs washing.

Also unfortunately, there is three tons of the stuff.

Actually it's not necessary to be too fussy when washing gravel as the system takes care of a lot of it, but this seems like very dirty gravel so it needs a good rinse at the very least. It's one of those things that takes so much work to redo if you don't do it right the first time, that its worth putting in the effort the first time.

I was hoping the truck might be able to deliver the gravel directly into the grow bed, where I could then rinse it with a high pressure hose. Unfortunately the grow bed was a bit too high for that, so it had to be unloaded in a pile next to it.

Its actually a good thing it wasn't able to be be dumped directly into the grow bed, because it had much more dust on it than I had anticipated.

Washing gravel is hard work with all but one method. Some bright person came up with the idea of just washing it with a fire hose when its in your trailer, or truck. By all accounts this seems to work well, so if you have that option, it's probably worth trying.

Its been a few years since I shovelled 10 ton of stuff from one spot to another, and in those few years, stuff has got a whole lot heavier.  Even when it only weighs 3 ton.

Unfortunately it didn't quite all get done.


Aquaponics - Media screen and standpipe

To try to keep all my gravel from grinding into the pump in my new system, I'm going to need a large media screen.

The media screen's task is to prevent any gravel from flowing out with the water. The easiest way to make one is to make it out of PVC. PVC is turning out to be my favourite material to use for all kinds of things during my time spent so far learning 120 things in 20 years.

The screen needs to be big enough to put my arm into in case I need to adjust something, or remove a snail or something. The PVC I'll be using is around 200 mm in diametre.

I cut a length at 400 mm because the plan is to make the gravel 300 mm deep, and to prevent gravel falling in when I'm digging around, it needs to be around 100 mm above the gravel.

I concentrated all the holes at the bottom, because if this device doesn't work well at the end of the cycle, when the tide is low, it wont work. Any holes at the top are not really needed if there are enough holes at the bottom.

Then Cleaned it up with a small hand held rotary tool. Any wire brush would do, or you can use a file, or even a drill bit a few sizes larger. If you use the bigger drill bit method you can just twirl it around at each hole even by hand. You also get very nice bevelled edges and it's quicker, but I didn't have a bigger drill bit.

The next task is to place it in my new grow bed, and fill the grow bed with gravel.

Aquaponics - Beasties

I found some alien beasties in my new grow bed.

It's not often that you get to mark out three square metres or so of clean wet stuff on a high contrast background, and see what moves in overnight. In the morning, there were some bug deaths, some bugs just getting on with their lives, and my first bug births. I have no idea what they are, but they only took 12 hours to move into my new grow bed. 

Very very small beasties

I put a few hundred litres of water into the grow bed to test my silicone, and to weigh it down.

I'm hoping the truck that delivers my gravel will be able to dump it directly into the grow bed saving me a stack of time. It wont be able to, but it keeps me from thinking about having to shovel gravel.

It's no wonder people buy bulldozers.

Aquaponics - Fish waste solids masticator

I guess it's just plain laziness, but I'd rather not chew my fish's solid waste.

Luckily shell grit is willing to do it for me.

This is as yet untested, and in my experiments so far, there are some potential stumbling blocks to overcome, but this is what I'm working on...

We need shell grit in the system to buffer pH, so I figured I'd put it to use to break down solid fish waste, before it enters the grow bed. This is probably unnecessary, but I'm hoping to distribute the waste more evenly throughout the grow bed. I'm also hoping to grow some strawberries in PVC pipes at some stage, so it will be necessary to have very clear water running through them so they don't block, as the roots will almost fill the pipes.

This represents a possible solution to keeping the water moving freely throughout my system, if I end up needing it.

The general idea is that fish solids enter with the water, and because of the direction of the inlet flow, they swirl around. The water overflows leaving the solids behind. In aquaculture, and sometimes in very densely populated aquaponics systems, this is employed with a tap at the bottom to allow removal of the solids from time to time.. It's called a swirl filter or solids filter. All I'm thinking about doing is adding shell grit to one, and making the grit and the solids tumble around until the solids get small enough that they rise up and overflow in the grow bed with the water. I don't want to lose my solid waste because me plants want all the nutrition that's in it. The general idea is that it should be a prefilter, and double as a way to add calcium carbonate.

In my larger system, I think I will incorporate a solids remover in case something goes wrong and I need to instantly lessen the nutrient load. I wont need to empty it in normal use, but I will have the option in an emergency.

Aquaponics - String feed counter

The small volume of the food that's being dumped each time my on demand feeder triggers makes it difficult to measure, so I've been trying to figure a way to register trigger events.

My fist attempt at measuring the times when my fish triggered the feeder was a small spot of blutack on the top of the shaft. If the shaft moved while I was away, I could tell. But it turned out that the shaft turned one full revolution on at least one occasion, so there was no way of know if the fish had triggered it or not because the blutak was right back to where it started.

The next was a small pebble that I could leave sitting on the top of the shaft. If triggered, I would find the pebble lying next to the shaft. This worked but could only measure one trigger event before I would need to notice it, and reset it.

My latest design is a piece of string attached to the shaft, with a nut on the end for a weight. When the fish trigger the demand feeder, the string winds around the shaft, and raises the nut up.

It wont tell me exactly how many times it was triggered, but will give an indication of how long the motor ran in the time since I last reset it. Each time the fish hit it, it seems to turn approximately one revolution, so I should be able to mark off a rough guide on the wood. This should make a reasonable gauge to tell me how active the fish have been in setting off the feeder.

Aquaponics - Demand fish feeder success

I think I can safely say my fish feed themselves now.

Its been only five days since the fish first set eyes on my on demand feeder, and in the last 12 hours they have triggered it around eight or nine times.

They seem quite casual about using it now. Although The smallest of the fish in the tank just lurks near the lever, looking up at it. This little guy spends almost all his time looking at the lever, waiting for someone else to press it.

Water tests are showing no ill effects from the new feeding method, although I wouldn't expect them to. Feeding gradually all day rather than in large lumps a few times a day, should see the ammonia load maintain a nice steady level. A stable ammonia level, in my case zero ppm, should allow for the bacteria to maintain a relatively stable population. As far as I can see it should make the system a little more forgiving, and generally more stable.

Another advantage is that there should be less wasted food. With my regular method of hand feeding, I fed the fish until they stopped eating the feed. This meant that every time I fed them, a small amount would be left uneaten, to sit on the bottom. This represents no great loss because uneaten food all turns to plant food in the end anyway, but the plant food may as well go through a fish before being eaten by the plants.

My next step will probably be, to add a hopper to feed the auger. This will only need to be something like an empty soft drink bottle upside down over the PVC chute. While I'm at it, it would be a good idea to weather proof and possum proof the entire device.

All in all this experiment has turned out to be a complete success.

The cost for the motor and gearbox was around AU$20. I used a short length of flexible plastic tube to connect the gearbox shaft to the auger, which I already owned.

Aquaponics - Slugs 2

In keeping with my policy of being wrong from time to time, it doesn't seem to be slugs eating my strawberries.

The night before last it was raining, and the slugs were out in force on the paths around the small aquaponics test system, so if ever there was a night for my trap to work, it should have been this one.

My beer trap managed to trap exactly no slugs whatsoever.

It did however manage to catch a number of very small flies. I doubt they could have been the culprits, but the fact that they like beer may indicate they like fruit. Often bugs seem to be attracted to the ethanol produced in decaying fruit.

My strawberries where in good  health, and not at all over ripe, so who knows.

I might try flooding my garden bed to see what crawls out.

Aquaponics - On demand fish feeder

A while ago I tried to make a fish fed fish feeder design that would allow the fish to feed themselves.

I think It's made.

I say "think" because the fish have only triggered it twice in its first 12 hours of it being set up in their tank, and it's too early to tell if it works.

I bought a small 12 volt electric motor and gearbox, and connected it to an old drill bit from a hand cranked wood drill.

I cut a section of PVC pipe lengthways as a feed hopper, and filled it with feed.

The gearbox on the motor means the output shaft spins at only 36 revolutions per minute, and is quite powerful.

The next step was to find a switch that was very delicate to operate, so the fish could just lightly touch it to activate the motor.

I found a suitable lever switch, and glued on a plastic knife to extend the lever down into the water.

Now if the fish touch the lever, the motor engages, rotating the drill bit, forcing a small amount of feed along the PVC hopper into the fish tank.

I added a key, and a clip from my office as additional weight to set the trigger closer to being activated so the the fish need not hit the lever so hard.

It does actually seem to work, and the fish have set it off twice so far.

Only time will tell if it will really work as a feeder, or if every now and again, a fish just bumps into it and never associates the drop of food with the press of the lever.

[Note from the future - there is a LOT more to this project in later posts, including a new digital version where you can set the total amount of feed from a pinch to a bucket, and a stack of other features including a dawn reset so the fish can live on natural time rather than Greenwich imposed human time - there is also a video of the fish feeding themselves, and here is the results of a search on this blog for fish feeder for a stack more information]

Aquaponics - Finished the new grow bed.

It took a few weeks, but I've finally finished the new grow bed.

It still doesn't have a fish tank, a sump, or any plumbing, but it should be ready for some gravel.

If I get gravel, I can start to grow some nitrifying bacteria. Then I'll be well on the way to a decent system.

I glubbed on a stack of silicone.

Weighted it down with everything heavy I could lay my hands on.

Until I saw a bead of silicone telling me it had covered the surfaces nicely.

Cleaned it up, and its done!

This grow bed has taken way too long to get finished. Especially given there wasn't really anything that needed to be done. It should have taken an afternoon rather then the weeks it has.

Aquaponics - Slugs

As much as I wanted to eat my first strawberry, it turns out something else wanted to eat it more.

I like slugs as much as the next guy, but now I like slugs as much as the next guy if the next guy has just lost his first strawberries to slugs the day before he was going to eat them.

If the neighbourhood slugs are willing to share their half eaten strawberries with the me, its only natural that I should be willing to offer them a small spill of my beer. So I will.

A beer snail and slug trap consists of a small bowl of beer. That's all it takes to draw all the slugs from my nice organic produce into the depths of depravity, and drunken stupor.

Unlike the thirty or fourty years it might take my fellow humans to die from over indulgence, slugs achieve this feat within hours. Or so I'm told.

I can wait all night.

Is there anything beer cant do?

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