George wrote:

"Roy" wrote in message
.. .


The propertys of the two clays are entirely different.......One will
do the job (supposedly) and the other is used by those that don't know
any different simply because its bentonite and they considfer
bentonite all one and the same, which it is not. i'm not gonna get
into a blow by blow difference in clays, as there is a heap of info on
the various bentonite clays, with a google search....



Roy. I'm a geologist, and have used both types of bentonites extensively in
my work. The question still stands. Why do you say that one is preferred
over the other for use in garden ponds? The are both highly adsorptive,
and highly hydrophilic, so what difference does it make? Although they're
chemistry is slightly different, their physical properties are nearly
identical.




Geeeesh! I just called a supplier here and the guy that answered the
phone says "what's southern bentonite or calcium bentonite?" "I just
have straight bentonite". Then he says, "who calls it that"?
Interesting...
W. Dale