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RE: Sexton's Search For Clay

Richard Sexton asked about the percentage of Iron which should be in clay
used in a substrate. I dunno anything about what "should" be there, but in
(http://www.actwin.com/fish/aquatic-plants/month.9706/msg00025.html), Onis
Cogburn, a potter, stated that the red color in pottery clays is caused by
Ferric Oxide and that one commonly available brand "RedArt Clay" contained
6%-8% Ferric Oxide.

To find a local source for this (it's expensive to ship), check your local
Yellow Pages under "Pottery Supplies".

Note that in my earlier posting I recommend that a quantity of Peat Moss be
mixed with iron rich clay to help create conditions where the Iron can be
made bio-available (plants can't use Ferric Oxide on it's own, as far as I

Another alternative, although one which would require waiting until Spring,
is to use a local clay (hey, it's FREE!). Richard has the good fortune to
live in Bannocburn, a small community 15 miles from Madoc (not too far from
Bancroft) in Eastern Ontario. A cursuroy web-search turned up some
interesting facts about the geology of this area, which is situated within
the Canadian Shield. The rocks in Richard's neck of the woods are
approximately 1.25 BILLION years old. A lot of the massive granite and
quartz deposits in this area are overlaid by beds of clay. (When I say
"massive", I mean REALLY big - one SINGLE rock in this area was measured at
over 30 sq. mi., and contains over 170 cubic miles of Perthite Granite!)

An aside, also of absolutely no use to aquatic gardeners, but interesting
none-the-less, is that Bancroft, Ontario is only one of 2 locations on Earth
(the other being in Siberia) where you can find samples (94%) of ALL the
known minerals found on Earth. One impetus that might spur Richard to
actually go out and look for a local source of clay is the fact that a 23
carat diamond was once found in the area... (Richard, check out the
following URL: http://www.bredberg.on.ca/bredberg/geo/madocg1.htm).

But back to aquatic plants....

Clay in a substrate works.... so does a high clay content sub-soil (check
Steve Pushak's web-site for a more complete discussion). While I was
personally sceptical for a number of years, after giving Steve's methods a
try, I'm a believer. It might take a bit of detective work with a web search
engine to find information about the local geology in a particular area, but
most people should be able to find a local source of a material suitable for
use in an aquarium. Any deficiency in Iron in a local source can be
supplemented with Micronized Iron and a few handfuls of Peat moss. If I,
living smack dab in the middle of Toronto can find not one but two pristine
sources of soil suitable for use in my aquariums within walking distance of
my home, Richard (and a lot of others) can do so as well.

James Purchase