Backyard Aquaponics
A place to discuss aquaponics

Hello AP experts...
I am starting up a system and i've decided to go with a mix of hydroton, perlite/vermiculite mix for grow bed but have noticed that perlite/vermiculite breaks down easily....
can perlite/vermiculite kill fish if they swallow it (only have goldfish so far)

Cheers,

Kam

Perlite & Vermiculite will breakdown over time Kamali, but usually don't do so with normal handling for at least 12-18 months.

How have you got you beds filled?? hydroton on top of perlite/vermiculite layer or vice versa?

Perlite/Vermiculite does break down. Perlite is the only one to be a little concerned over. It is basically an expanded mineral which can feel like fine glass particles if crushed finely. I would imagine if you had a lot of this in contact with the fish you may have issues. However being a relatively heavy substance it should just sink to the bottom of the growbed and not cause any harm.

Vermiculite may stay suspended in the water, but I have no reason to be concerned over fish consuming it.

i used the 50/50 perlite/vermiculitemixture in my setup and it didn't bother the fish. since i ditched the chemical declorinator i haven't lost a fish (4weeks)
i wouldn't use it again though. the vermiculite tends to block pipes

What about Zeolite - it has the ability to store and slow release nutrients and also sucks up ammonia.

Re zeolite: We want the ammonia...to change into nitrite...to change into nitrate....to feed the plants. Something that absorbs ammonia is only good for a short term fix if you are having an ammonia spike.

using vermiculite depends on where it has been mined. You might be OK if it is a locally mined product. there has been a lot of discussion here in the states with regards to asbestos contained in some vermiculite sources. Albeit it is small quantities of asbestos that is found but even small can do lots of damage to the lungs.

DRD, being that it's kept damp at all times, and that if the fish ingest it and then you do; is it such a problem? I can't imagine it finding a way to your lungs? Or have I overlooked something?

Both Perlite and Vermiculite can be quite dusty when you handle them....

Basic precations apply.... wear a mask....

Perlite dust can contain minute glass particles that can rip your lungs... and yes some "old" vermiculite mines did contain a level of asbetos

I don't believe this is the case in Australian vermiculite products... i'll check....

Edited : Link to a general explanation of the topic...

http://www.vermiculite.net/

Exfoliation? I know it's a touch off topic, but isn't that the removal of skin cells?
There was a definition I just googled that said plants 'exfoliate' as they grow, in a unfolding leaf pattern.
If you heat vermiculite, and it expands, will it contract when cooled, or does this 'exfoliating' process mean that it sheds layers and then is permanently changed?

Exfoliation as a "geological" process Kuda

http://en.wikipedia.org/wiki/Exfoliation_(geology)

aha, so if it expands, it wont retract again, it just busts up into little pieces, that don't fit together again so well, so take up more room.
Cheers Rupe, I didn't see that when I checked wiki...