Filtering Poo with Continous Flow Media Bed

My indoor system started out with a gravel bed. After repairing a leak in the 45 mil EPDM liner of that grow bed, I decided to go with a Deep Water Culture (DWC) raft.  With only one 10 wall glazed my grow bed is 30"x10 long which is a rather small 25 sq ft..  I found it easier to utilize that precious space with a  raft system.

A panoramic view inside grow room.  800 gal fish tank on left grow bed on right

But loosing the large media bed meant that I would also lose the filtering capability of the 3/4" rock media.   So I decided to build a filter using evaporative cooler pads.   This works great at first, but after a few months the fish population began to grow and the fish got bigger.   The filter could no longer keep up with the poo.   Cleaning filters everyday was more work than I was willing to do.

So I decided to return part of the bed to a gravel media, and keep the rest as a DWC grow tank.

The DWC tank with gravel to the right of a plastic fence partition

I built a partition out of plastic fencing and PVC pipe.  Filled one side with 3/4" gravel and extended the return water pipe from the fish tank so that it dumps on top of the gravel.   One thing Id like to say about that is I also used 2" pipe rather than 1-1/4" because the smaller pipe tends to clog.

At this point I began to have concerns about a continuous flood gravel bed.  RupertofOZ was kind enough to dispel my fears by pointing me toward a very good experiment done by backyardaquaponics.com.  

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Aquaponics Shell grit seed raising

It seems like Ive been trying for ages to find a decent method to raise seedlings from seeds.

My preferred method would be to just throw them all over the place and see what happens, but I suspect the clay ball media allows seeds to fall way down into it. Its possible that with the normal vibrations of city life, that the seeds fall all the way down into the water and then sink to the bottom and rot.

One problem with raising seeds in potting mix is that you do a lot of damage to the roots when you wash them before transplanting them into the aquaponics system.

I add shell grit to the system as a pH adjuster. The nitrifying bacteria tend to move the system toward the acid side, and the shell grit brings the pH back into line (approx pH 7.0).

So I figured it might be a good idea to raise my seedlings in shellgrit.

I started with a food container, and drilled a few holes around the base.

Then added the mesh from a stainless steel sieve, and filled it with shell grit.

Shell grit can be bought where ever you might buy chicken feed, as they sell it to people who have chickens. Chickens eat it and it helps make their eggshells strong.

I chose a space close to the water inlet in the growbed to bury it so the water flowing through would have high levels of dissolved oxygen. I figured this might be important as the flow through the tightly packed shell grit would be slow.

I buried it at a depth so the water level just reached the shell grit. The water "wicks" up through the shell grit so it stays moist.

I also added a lid in the form of another food container.











Im not sure if the lid is needed, but a lot of store bought seed raising trays have lids so I thought Id add one. It probably isnt required because Id guess the lids are used to keep the moisture in, but with water always wicking up from the bottom...

Who knows.

I have no idea if this will work, but as always, Ill let you know one way or the other.


120 Things in 20 years - My ribs hurt.

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Aquaponics Flow meter

I got up in the night a week ago, went for a stroll through my house, and promptly fell over a lump of furniture nesting in my hallway. The last few weeks has seen us deciding that we really dont need a ... whatever you call that room with couches and a TV in your part of the world ... living room, lounge room... something like that if you speak English. Anyway, we decided we dont do enough "living" or "lounging" to really need a room dedicated to it, so we filled it full of floor to ceiling shelving, some desks and benches, and turned it into something more like a factory. A factory that doesnt actually produce anything, but does a heap of product development.

We figure when we want to entertain, well just do it at our guests house.

The result of all this that meandering about our house, is a river of transient furniture acting as flotsam and jetsam and nesting where it feels most comfortable, or simply where it last got stuck.

The result of that, is I tripped over an upturned thing with casters on the legs and impaled myself in the lower rib cage.

The next day I went to a doctor with a temperature of 39.7 c.

Who knew falling down gives you a temperature?  The doc thought I had ruptured my spleen so he suggested I go to hospital. The hospital decided I had three cracked ribs and pneumonia. A week later they finally disconnected all the feeding tubes, the morphine drip, and the catheter and let me go home.

The interesting upshot of all this, is that as a result of being given some kind of lung exercise device, I now have an excellent flow metre for my aquaponics system.


Which is nice.

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Photography Photo stacking

Ive been reading a bit about photography, and discovered this thing called "photo stacking".

It helps you create super close ups that have everything in focus.


Normally in a photo, you get some bits in focus, and some out of focus.

This can be a good thing, because you dont always want, for example, the background to be sharp.

Sometimes things look better when you cant see them.

But sometimes you want to see it all.

Ill drop a series of seven photos here with each one seeing a different section in focus.

This first pic of a 300mm ruler is taken at a focal length of 10mm.

This next pic is at 20mm

You can see that the section thats in focus has moved a little further back.

This one at 50mm

 Here are three more in the series with each one seeing the focal length change through 100mm, 150mm, 200mm, and 300mm.

I would have preferred to use increments of 5mm all the way through, and take 60 photos, but this camera I have only deals with those photo lengths when used in manual focus mode. 

There is software that is free and open source, that can take the best bits of each photo, and knit them all together to make one photo. 

Apparently its possible to do this in a graphics program, but I dont have the skill set, and the software seems to work. 

There are a few different software packages, some that cost and some that are free. The one Im playing with is called, CombineZP. All you have to do is select the photos (New), then chose something that I dont understand called, "align and balance used fra..." (the title of this function is cut off because whoever made it doesnt respect my inalienable right to resize whatever window I want, and my screen size isnt the same as theirs), then click something that makes perfect sence that says GO.

After a few seconds wait, the end result is pretty good for a first attempt, and might just prove to be a very useful tool in trying to capture extreme close up shots. 

Im guessing it would be perfect if I just had a camera that could deal with letting me chose where to focus all on my own. 

Even without respecting my free will, the result is quite good. You can see in the photo below, some bands of blur where I couldnt divide the focal length and add another frame. Theres an obvious blur between the "k" and "i", and another at the "3" in 300. Another at 250, but they are all errors caused by my camera not letting me take pictures in between the ones I took. 

Tis an interesting bit of kit, and I thoroughly recommend trying it if you are taking macro shots. 

 

The result...

120 Things in 20 years - I love discovering new things like photo stacking for macro shots, and I love discovering that there are only 6 photos in my series of 7. I deleted one, and have no idea which one it was, so I moved on. 

Im also without confidence that Im using the words "focal length" properly. 

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Aquaponics Strawberries

Yum.

I love strawberries, and spend way too much money each year in keeping the fridge stocked.

I cant get enough of them.

Here are some free strawberries  from the backyard.









Some are from the aquaponics system, and some from the dirt along the side of my house.

I planted a stack in one blue barrel grow bed, and a stack more in the ground along one side of my house.

The strawberries grown in the aquaponics system are always bigger and juicer. They also look better. Always big and perfectly formed. But Im not convinced they taste any better. In fact I think the ones out of the ground may actually taste better.

When growing grapes for wine, I understand you dont want too much rain as this makes the fruit bigger, but lowers the amount of sugars per lump of grape.

Or so Im told.

This might have something to do with why the strawberries seem to taste better out of the ground. The ground strawberries get watered once a day when its hot, and every couple of days if its not.

The aquaponics strawberries have as much water as they want when ever they want it.

Or...

It could have nothing to do with that. I cant be sure which went where, but there were two batches of strawberry plants. One batch was fully grown mature plants, and the other batch were all new runners. I seem to remember planting the runners in the aquaponics system because they were smaller, and I wanted to see if they would catch up to the others. But I also remember not doing that. I remember mixing them up so I would get a sample from each. I remember a few other contradictory things as well.

So... possible that they taste different.

But I think its going to prove to be water content.

I think Ill do some experiments with the runners from both batches to see if there is any difference when all plants are the same age. Both beds are producing runners, so I think I should know within a few months.

Another thing to try, might be to change how long the aquaponics plants have wet feet. I should be able to control very precisely how much water the plants are exposed to.

I have an electric tap from a sprinkler system, so I might try to make some kind of moisture sensor, and perhaps try letting their roots get almost dry before giving them more water. I have no idea if such a thing is even possible, so Ill find out.

Or...

It could be that the strawberries dont taste as good when they are hot. Very few of the fruit ever make it into the house. Most get eaten straight from the plant, and there is a huge difference between the temperature of the narrow, protected side of the house, and those grown in a hot house. Now that I think of it, I think strawberries grow well in places like England. Im not sure if England is called England or not, but that place thats sometimes called England seems to be the kind of place people grow things like strawberries.

Perhaps a hot house makes the fruit taste different.

Ill have to find some more information.

Im being very fussy here.

All the strawberries from my back yard taste much better than anything Ive ever bought from a shop. Shop strawberries are always under-ripe, and seem to be made of something other than strawberry.

Thats store bought on the left, and back yard grown on the right.

Even with this poor photo, you can see the difference.

I can also smell the difference.

And if you drop a store bought strawberry into a clear drink, you get a strawberry in a drink. But the back yard ones colour the clear drink strawberry colour.

I count aquaponics and dirt grown strawberries as a total success.




120 Things in 20 years - I think Il buy a second hand digital SLR camera so I can take better photos of strawberries and.

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Aquaponics New growbed flow control

I few days ago I created and installed all the required bits to control the way water enters and exits my growbed.

All this is probably overkill as a lot of people get away with just dumping water at one end, and draining from the other, but theres a fair chance that at some stage down the track I might try to make this system ultra low energy, so I thought Id design it so the water can move very freely through the browbed, and so it doesnt leave any areas that dont get enough flow. If I go low energy, that might mean low flow, so I designed it to what I think is the best way I could.

The plan is to have the water enter into a submerged pipe at one end of the bed that has a lot of holes in it, and exit via a similar, submerged pipe at the other end. This way the water will enter and exit evenly throughout the width of the growbed ensuring that no corners are left to go stagnant. With high flow, this wouldnt normally be a concern, but I wanted to make sure I had lots of options for the future.

After a bit of experimentation I discovered the quickest and easiest way to make holes in PVC pipe for water flow was with an angle grinder.

Just a normal metal cutting blade does a pretty clean job of cutting a lot of slots in a 90mm PVC pipe.

Just tap it onto the PVC quickly and it works a treat. A one second cut is perfect. Three seconds will burn it.






Slots are a must when using the clay balls for media as if you drilled holes, the balls would block them all.

All sized balls will block all sized holes regardless.

Go with slots.

The end result looks like this and only takes around 5 minutes per meter at most.

I cleaned it up with a little sand paper and added end caps and an elbow.

I cut a hole with a hole saw so that I could add a stand pipe that would go through the elbow, then continue on through the growbed.

Theres no great need to make these joins exact because you want water to seep in all through this bit of kit.

I  found some fittings that for some reason have a tapered thread.

When I got them home, I found that the things they screw into dont, which is kind of strange.








The original idea was to cut a hole through the growbed, and screw the two pieces together from either side to lock the fittings on tight.

Because of the taper, I ended up just making the hole in the growbed really tight, and screwing the fitting in really hard so it cut its own thread into the growbed.

It seems solid enough.

This is what the finished drain looks like. This will drain water from the growbed back to the sump.

A pipe will be fit into the recess at the bottom, so that even though the water enters the drain from the bottom of the growbed, the water will exit the device at a bit lower than the top of the growbed.

I cut a hole with my hole saw into the bottom of the growbed.

This is an oddly scary thing to do.

Shiny new water tight containers dont lend themselves to be holed without causing some distress to the new owner.

I cut the hole slightly smaller than it needed to be, and then hand filed the rest so I could be sure of a very tight fit for the threaded component.

Once coaxed through the hole in the growbed, the standpipe was cut to size, and pressed into place without any glue.

Theres no need to glue it because if it leaks, water wont actually leave the system, and there might come a day when I want to adjust the level, or change the system from constant flood to an auto siphon or something.

The drain assembly looked like this when fitted.

The standpipe runs through the growbed on the left hand side.

The other end was completed in a similar manner, but this time with a central inlet because there was already a hole in that position.

This is where water will enter the system from the fishtank.

And thats it.

The growbed part of the system is complete.

Its worth adding plastic caps top the top of the inlet and outlet media guards to keep the clay balls from getting in when your digging around in the garden.





Like I said, its probably overkill to make the inlet and outlet pipes like I did here, but it should make it just that little bit more efficient.


120 Things In 20 Years isnt above pretending to make a new growbed when really I made it more than a week ago.

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Aquaponics Over Flow

I wandered out to my system last night, and had what is commonly known as an HSM.

It must stand for Holy Ship Moment.

One of my grow beds was flooded, and there didnt seem to be any reason why.

This is the scene a few minutes after the pump was switched off.

There was water on the floor, and the pump was sucking in small air bubble through the little tornado that had formed in the shallow water over the pump inlet.

I couldnt figure out what was going on, so did a search of the system.

I found this blockage in the stand pipe.

It was stuck really well, but eventually to hammer it out with a length of dowel and a hammer.

The culprit, shown here, was a small piece of scoria.

This growbeds media is scoria.

I also found bird droppings. Im guessing a blackbird was in there throwing things around and looking for worms.

I do actually have an over flow pipe, added when I first built the little system, but the input flow from my bigger pump is much greater these days, so the little pipe wasnt up to the task.

Even so, its a good thing it was there because I think it saved the day by delaying the disaster until I discovered it.

Ill upgrade the pipe to cope with the new greater flow, and Ive put a PVC cap over the media guard so that particular issue cant happen again.





120 Things in 20 years think the last thing an aquaponics system needs is excitement when it comes to overflows.

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