Aquaponics - Settled media

As I mentioned in this post on moss growing on my media, my grow beds seemed to have settled since the move, and are perhaps getting too wet at the surface as a result.

I think it's officially causing problems.

At one stage my media was up near the rim of my blue barrel, but now it sits here.

That's around 100-120mm down from the top, so I can easily fit another bag of scoria on top. This would increase my filtration a bit as well as keeping the surface a bit dryer.

My media is still getting wet on the surface in spite of my trimming the stand pipe by around 15mm. I trimmed it a few weeks ago, but either it wasn't enough, or perhaps the moisture is coming down in the form of grow house rain, rather than up from the bottom, via the pump.

The media that is wet, is the stuff that tends to sit a bit lower than the surrounding media, but it could still be from "rain", and is simply not drying as quickly as the higher sections. I'm only talking about 10mm between the high and low sections.

One down side is that just as my first strawberry was starting to ripen...

It also started to rot where it was touching the damp scoria.

I really wanted to eat that strawberry.

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.



Delicious!

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 - New grow bed

Scoria has always been the media I favored because its perfect for aquaponics. I'll be using road gravel.

Here's some I prepared earlier.

Pictured here, and using chicken feet for scale, is a  path in my back yard. It's the same stuff I'll be using in my new grow bed. It's sometimes called blue metal, and in this part of the world we mix it with tar, and make roads out of it.

Scoria is great in all kinds of ways, but it's hard on the hands, and because of it's sharp edged irregular shape, it's actually difficult to dig into.

My new grow bed is big enough that I don't need to worry about the extra surface area scoria would provide. I'll get around 2000 - 2500 litres of gravel to fill it, and I'll use the existing system as a pre-filter to seed the nitrifying bacteria.

In a former life, this new grow bed of mine was an abalone growing tank used in aquaculture. As soon as I can stop switching between plans, I'll bu using it to grow veggies.

Aquaponics - Home made media

I did an experiment last night where I mixed some clay soil from my backyard with some crushed up goat dung. The plan was to try to make something like scoria, for use as a home made media for a grow bed, but just to see if it could be done.

And voilà!

First, I spread some whole dung out on a tray. Then I made a mixture of clay,water, and powdered goat dung. My theory was that the powdered goat dung would create thousands of tiny holes in the finished product. This would create some happy housing for the nitrifying bacteria required by aquaponics.

I then poured the mixture over the tray of whole dung. The design behind using the whole dung was an attempt to make it break into irregular shapes later on in the process.

Next I set it out to dry. If I was making an amount greater than this tiny test, I would have poured it onto the ground in the sun. But it was raining so I put it on some foil, and dried it on the fire. DONT DO THIS AT HOME! It can smell a little agricultural. When the yelling stops, you know your tile is dry.

Lay it out and build a fire over it. You want your fire to be 900 deg C or more. Clay will undergo a permanent chemical change at around 600 deg C (don't quote me on that number) where it becomes no longer possible to wet it back down to clay. The physical water steams off at 100 deg C, but at those higher temperatures its not just drying the clay, it's actually changing it into something else.

I actually fired mine in my living room wood burning heater, but to make it properly you need the kind of temperature that makes iron glow bright cherry red (~900C) It's quite doable in a decent fire.(a match burns at around that temperature).

A normal pot would crack if treated like this but because there is so much organic matter leaving the clay body porous, we can get away with it. It doesn't matter if it cracks anyway.

Next. Smash it.(see)

Its done (see top pic)

Delicious.

I have no idea if this is practical or useful in any way to anyone, but it was in my head so it had to come out.