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RE: Laterite

Richard Sexton is wondering about laterite -

>Ok, so whats the deal with this stuff? Is red potters clay good enough ?
>is kitty litter as good ? Does the brand of laterite make any difference ?

>The Dupla stuff was supposed to be from Malaysia as far as I know, will
>laterite from other countrues work ?

For a discussion of exactly _what_ laterite is, try this URL -
http://www.dupla.com/e037.htm. It is an article by Kaspar Horst (Dupla
co-founder), which appeared in the German language magazine Aquarium Heute.
There is also a lot of information in the archives of the APD on laterite
(thank's to the Geologist's on the list).

Red potters clay (Red Art Clay is the brand I'm most familiar with) is not
laterite. It has _some_ properties which are desirable for our purposes
(high iron content, high CEC) but others which we don't (it can form an
almost colloidial solution due to how finely it is ground).

Kitty litter is not laterite (not even _close_). Most kitty litter (the
kinds made of clay minerals anyway) is made from Bentonite (Fuller's Earth),
a type of clay which absorbs moisture and expands when wet, forming a rather
gelatinuous, gooey mess. Why someone would want it in their aquarium
substrate is beyond me (Dan Quackenbush be darned).

Laterite is:
 1.)a type of clay
 2.)high iron content
 3.)has suffered heavy leaching
 5.)under tropical conditions
 6.)over geological time.

There are many types of clay - the term clay only really refers to the
particle size of the material. A number of clays are available which have
high iron content - the red colour in some "pottery clay" is generally due
to the presence of iron oxides. The unique properties of laterite which made
Dupla (and several other companies) sit up and take notice are due to the
last three points - highly leached, formed under tropical conditions over
geological time. Dupla obtains their laterite from locations which have
tropical conditions now, in the  latter years of the 20th century. But the
laterite formed hundreds of thousands, if not millions of years ago. Back
then, (I was only young, so my memory may be spotty) the geography of the
planet was quite different from what it is today - coral fossils have been
found in the Canadian Arctic, indicating that at one time the land area
there enjoyed tropical conditions. Most of North America, at one time or
another, was tropical. I grew up in eastern Canada, on the island of Cape
Breton, and the eastern end of the island has extensive coal supplies -
these formed millions of years ago from tropical swamps. The place is far
from tropical in the modern era.

So, it is quite feasible that true laterite exists in North America. Karl
Schoeler's company sources Substrate Gold, a true laterite, from North
America, and from what I hear it is just as capable of working in an
aquarium as Duplarit G. The enterprising aquarist could consult local
Geology Departments to determine if any deposits of the stuff are in their
area, or they could just contact Karl and buy his product (it is cheaper
than Dupla's stuff). There are also other commercial sources - I understand
that Red Sea has just introduced a Laterite substrate additive.

So Dupla's departure from the "New World" need not send us all into a tizzy.
We, and our aquariums, will survive. I just won't have as many high tech
toys to play with.

>FWIW, the first real luck I had with plants was when I was in '73
>or so when I dug up some red clay from my back yard and put some
>in the bottom of a small dish, covered it with gravel and stuck
>3 Aponogeton crispus (or what passes for crispus) in it. They
>filled a 30 gallon tank.

That doesn't surprise me a bit Richard. By any chance were you living in
Toronto at the time? The Don Valley Brickworks, just down from where I live,
has deposits of clay which according to my research have lain there
undisturbed for the last three hundred thousand years. I've got a number of
pots of aquatic plants growing in the stuff and they are doing great.

James Purchase