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re: Surface area of clay and crushed fired clay



> Steve Pushak wrote:
>
[snip]
> Mineral diffusion from a fused material such as crushed
> ceramic (fired clay) will be much slower because of the
> smaller surface area of contact.

I think on whole I would agree.  But the firing process creates a
product whihc is porous,  I believe about 50% or so of weight of
the original product.  So it has helped to  _expand_  the original
surface area.  Like other porous substances, there are many internal
surface areas which have the benefit over gravel of filling with
water,  creating I would believe a more oxygen rich substrate. I
don't want to begin guessing what effect that would have on the
different chemical and biological process compared to gravel or
if they make a measurable difference.

> I ... meant to ask Greg about the possible organic content
> of Fluorite ...

doesn't organic suggest carbon which suggests it will be significantly
altered when subjected to heating?

[snip]
> My speculation (guess) at the composition of Fluorite is
> based solely on the premise that a "good" substrate -might-
> contain all macro and micro nutrients in appropriate dosages.

I suspect the heating process also alters the nutrients to some extent
depending on the nutrient, the amount and temperature of the heat, rate
of cooling, etc.  I have lots more questions here than answers.

What I would like to believe is that the heating process at least preserves
a CEC though as we both elude,  there are fusing and expansion (porosity)
issues.  I would suspect that with sufficient heat some clay minerals could
even be altered chemically so they form new species,  with new properties.

I had sent Seachem an email at some point asking if they would like
to test the Flourite for CEC before and after heating.  I also asked if it
would  be possible to define it in terms of mineral content (sort of like
the guarenteed analysis they provide for Flourish!) so we could
understand it more that way. No response yet.

Christopher Coleman
christopher.coleman at worldnet_att.net