Backyard Aquaponics
A place to discuss aquaponics

yes i do use seasol and cleated iron and im getting good results considering the growbeds age. I understand that a new system is better off being above 7 then under it as its only ever going to go down. I was just making the point that hebel or any concrete product is going to be over alkaline and based on my experience not suitable.
Thanks for easing my mind Rupe as i had tried hydrochloric acid but after the first few litres i decided it made no difference as it just buffered back within 4 hours or so.

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IT'S NOT YOURS UNTIL YOU'VE MODIFIED IT!

Sorry if its mentioned elswhere but:
What does it cost in Perth these days to fill a standard Backyard Aquaponics bed with expanded clay??
At the moment I have a standard bed with pea gravel and was thinking of getting another bed, emptying half the pea gravel into the new bed and then topping both beds up with expanded clay. Is this a good idea?
Dave

Perfectly fair idea Dave... a standard BYAP growbed requires 10 bags of expanded clay...

You'll pay anything from $30-$40 per bag... ask Joel for his best rate...

How long does the expanded clay last? Does it get "dissolved" over time at all?

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http://www.fishyplants.com

My blue barrel system must be near five years old... never done a thing to it... expanded clay balls just as they were on day one...

Fired clay in used in lots of pottery that is used for cooking and dish ware. Seeing as there are pieces that have lasted for hundreds as if not thousands of years, that the LECA in you GB should last for a very long time. As long as you don't crush them.

I live in Naples, FL - S of Ft. Myers (50 miles) and Tampa (179 miles).
I'm looking for the expanded clay rocks/balls. Does anyone know of a place for balk orders or where I could pick up supplies?

Candy, Home depot sells them and will deliver for free. Around $30.00 a bag. Go online, as they don't sell them in the stores.

Clay does not expand when moisture is removed. Some clay minerals will expand when wet, but they contract when dry.

As I understand it, the bloating is caused by over-firing ie too high a temperature for the clay. As the clay starts to melt if there are still volatiles turning to gas, you get bubbles trapped in the body.

A much easier way to create this effect is to add something like sawdust to your clay. it wont be quite the same as the bought ones, but it should be pretty easy to make.

Put clay and sawdust into a cement mixer and add water slowly until it balls up into the right size balls.

Dry them for a week preferably spread out. if you can spread them out and they are in a barrel or something, make sure there is airflow through it and maybe dry them for longer.

put some on the ground, add some hot burning wood, then more balls and more wood.

If your going to sit next to it, it might be a good idea to wear safety glasses as there will be a few small explosions with the potential to send flying bits of clay around. Having said that I would have no problems about doing it in a suburban back yard. The explosions would be just like a fire that's spitting a lot. some of that spitting is probably the ground or small stones.

Terracotta clay might normally be fired to 1000c or a little more in my case, but this ie easy enough to reach in a decent fire. Iron glowing cherry red is around 800c-900c.


I've never done this, but have been a potter for a few decades. I also on different occasions have made the balls accidentally, have made pots with organic stuff that's burnt out, and have also made a test batch of home made goat dung scoria fired in my lounge room heater..

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My system

120 THINGS IN 20 YEARS - My blog about my learning adventure

My skills include being able to move slowly forward in time, and if I really concentrate, I can sometimes tell what I'm thinking.

Anyone have an update on good clay pricing in Perth for a 50l bag?

Also how much clay bags of 50l would I need to fill a 350l grow bed?

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The brave may not live forever....but the cautious does not live at all!

My first sentence wasn't very clear.

Clay bodies have a temperature they like to be fired to if you are trying to make a pot that is waterproof, and that stands up without melting into a puddle of lava.

A clay like a porcelain will vitrify (fuse together like glass and get all waterproof) at perhaps 1300c.

If you fire a clay like terracotta to 1300c, you will get a puddle of lava. A terracotta clay might prefer something more like 900c to 1100c

We fire ours to 1080c. If we push it an extra few degrees, we start to see something known here as "bloating". The surface of the clay glasses over, and then various stuff under the surface continues to to turn to gas. This creates a stack of tiny bubbles (or sometimes they turn to one big bubble) and means you don't make any money. They form a lump on the side of your pot that could be as large as ... say... a grape or larger. This tends to look like a thin, glass, bubble gum like blister, rather than a nice expanded clay ball suitable for aquaponics.

Adding sawdust or something similar that will simply burn out at your firing temperature will allow you to fire just high enough to make the media stable and not dissolve over time, but wont require any special equipment.

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My system

120 THINGS IN 20 YEARS - My blog about my learning adventure

My skills include being able to move slowly forward in time, and if I really concentrate, I can sometimes tell what I'm thinking.

Oops, ignore whatever I said in my last post that may have been said here...

Are you a potter Bullwinkle??

I love working with clay, though it's been a while...

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If you give a man a fish, he can make an AP system, but if you give a man too many fish, he'll probably have problems with ammonia.

Barrel System
IBC System
300 gallon flood and drain system