Aquaponics - Easy automatic duckweed feeder

Sorry folks, just a quick proof of ID.

Hi BYAP.

Actually I do have something to post though.

I had another idea for an automatic duckweed dispenser, and it works!

The previous one looked like this...

Or this from the side...

In this new easy one, all you need to do is pump some water into a pond a that's a bit higher than your fish tank, then create a flat spillway that falls into your fish tank. Make the spillway quite broad so the outflow is slow (or have a low flow to the duckweed growing tank). The idea is to not have the duckweed all flow out. A good way to do this is to create some texture on the flat spillway. paint on some silicon mixed with some fine gravel or something. 

It's a good idea to add water to the duckweed pond so that the water swirls. This way the duckweed builds up in the middle, and less will flow out at each time it triggers.

If the flow and texture is correct, the duckweed wont flow over because it gets a bit stuck on the spillway. 

After a while, the duckweed grows thick enough that it blocks some of the water. In my little decorative system, I get a rise in tide of around six or seven millimeters before the pressure builds up enough and dumps about ten percent of the duckweed into the fish tank. 

It wont dump again until the duckweed has grown back.

The result of this is that you never run out of duckweed, you feed more duckweed in the summer (when duckweed is growing faster, and your fish want more food) and it's automatic.

Not a lot of posts for ages. but I'm still doing stuff. 

Electronics - Motor repair success

I fixed my broken motor that is meant to power the auger via the tiny gearbox that will deliver the fish food in my demand fish feeder.

Normally I prefer less complicated sentences.

But I'm all excited.

It turns out, the problem was there were simply too many parts.

Or more accurately one too many parts, and one that was simply in the way.

The silver bit was the one too many. I think that broke off the bit where the wires connect, and fell into the motor, generally clagging things up.





The little nylon washer creates part of the front bearing, but it made getting the brushes back on impossible, because it had to be put on after the brushes. That's an impossible path through the plastic front. I don't have the kinds of quantum tools that walking through walls requires. And if I did, I wouldn't waste my time with motor repairs. I'd do much more interesting stuff, like poking my head through the fridge to see if the light really does go off when the door is closed.

So be leaving out those two small parts, I managed to make my motor work.

Only two parts.

And they were tiny.

Those that know me will realise that's a pretty low number of excess bits after a repair. I think I did quite well.

So well in fact, that it looks like this when it's running.

That should do nicely.

What this all means, is that there is really no reason why I cant put this thing together today, and actually finish something.

Maybe.








120 Things in 20 years - If I keep repairing them, one day an electronic motor repair might leave me with enough parts to eventually build another motor. I should fix cars.

Aquaponics - Colander feeder success

Well that was easy.

Not that it was ever expected to be difficult, but the fish found the food within a few hours of swimming endlessly in circles.

Fish are so smart.

I've already started to raise the feeder up each time I feed them so that eventually I can add feed directly from the surface without having to lift the colander.

If I feed from the surface with the colander at depth, the feeds blows away in the current before it reaches the sheltered waters of the strainer, and then gets sucked into the outlet before the fish even see it.

The colander will also allow me to trap any fish I choose with minimum fuss and stress. All I'll have to do is lift it to the surface when my chosen fish is in and it will be caught.

It will also serve as a measuring device as I can stick a stainless steel ruler in it to compare fish to each time they enter.

Is there anything a stainless steel colander cant do?

I also replaced the PVC hide for the little one, but this time I cut the sides so it stands on legs, and raises the walls up off the ground so solids cant collect.





120 Things in 20 years is one of the few places on the net where you might hear someone banging on about an aquaponics, colander feeder success.

Aquaponics - Colander feeder

One of the requirements for a SLO (solids lifting overflow) is that you need to concentrate the fish solids with a whirl pool.

One of the issues with making a whirl pool in my fish tank is that it's a cube.

I found by pointing the powerhead, I can make the solids collect where I want, but the result is that any feed I put in tends to be removed as soon as it hits the bottom before the fish get at it.

I figured I needed something to hold the food off the bottom until the fish eat it, so I made use of a large kitchen colander.

I hung it by three strings, and then tied an extra string in a loose loop around the three.

That's the three strings going off to the right, and the loose loop going off to the left.

The result is I can pull the thing up to the surface and to the side by pulling on the loose loop to add the feed.

Then I can just let the thing go to slowly drift back to the centre, where it remains suspended a few inches off the bottom.

I found that anything sitting on the bottom was collecting solids so I keep it high enough to allow a free flow under and around it.

The result is any solids can go straight into the SLO and to the grow bed, but any food hangs around until it's eaten.



The other result is that it's driving my fish crazy as they can smell the food, but haven't quite got the hang of going over the top rather than trying to eat it through the holes in the strainer.





My new 120 things in 20 years, Aquaponics - Colander feeder fish frustrating catch cry is "They'll figure it out".

Aquaponics - Fish feeder

I like to invent stuff.

I also like my fish to be fed.

I'm going to try to combine my two likes into one uber-like.

There are probably a zillion ways to do this but I can only think of a few.

A tiny electric motor with a reduction gearbox would do the trick. If the gearbox had a reduction ratio such that it turned a drill bit extremely slowly, you could drill a hole through a plastic bottle, fill it with fish feed, and then poke the device through so that as it turned (very, very slowly) the drill would push feed out at a constant rate. Or you could hook it up to a small solar panel and make it work only when the sun was out. You could also connect it to a timer to create preset feeding times so as to be able to control exactly how much food to offer.

In order to gear my chip cooling fan motor down from around 3200 rpm, I had to jump through some hoops. To get it to turn as seen in the video, I started my reduction gearing by having the near center surface of a rotating computer fan rub against the outside edge of a fan from an old photo copier. This fan is connected to a gearbox reducing rpm even further. The photo copier fan and gearbox were connected via the thin shaft by rubber band to a thicker shaft made of PVC. The PVC was connected to the front of a fishing reel. The fishing reel acts as yet another reduction gearbox. The handle of the fishing reel was connected to a soft rubber hose to act as a uni-joint, allowing me to not have to attempt to be fussy with lining up the drill bit that went through a soft drink bottle. As this all rotated my chickens ate the delivered bird seed under the decking.



This is still turning way too fast to be useful unless connected to a timer. It's also way too zany to be put into actual use.