[APD] Re: Flourite vs soil

["James Purchase" <jppurchase at rogers_com>]

Cameron James asked:
"A couple of kilometers from my house is quite a mountainy area which is
rich with a very fine reddish sand, do you think this type of soil would
have been a better option over the plain brown dirt?
Is the soil a reddish color because it contains a high count of iron or is
this caused by something else?
When setting up your soil based tanks did you add large amounts of humus
under the soil layer or perhaps mixed in with the soil? I seem to recall Tom
Barr saying that he uses a half inch layer of humus mixed with vacuumed
detritus from an existing established tank, covered by a 2-3 inch layer of
the soil and then capped off with 5cm or so aquarium gravel. I am planning
on using this recipe but would also be interested to hear of your methods if
you don't mind as you seem to have good experience with this type of setup.
Thanks a stack for any input or web links offered."

"Redness" in soil and rock us USUALLY caused by Iron Oxide, which over time,
can be converted into a good source of Iron for your plants. Soil for your
backyard might work - it depends on where you live and what has been on the
site in the past, or where the topsoil was trucked in from.

When I am looking for a topsoil or a subsoil for aquarium use, I like to do
a bit of research on the geology and history of the site first. The geology
can tell you what kind of minerals might be in the soil and the site usage
history can help you avoid any site previously used for industrial purposes.
A mountainous area is likely to be a good source - the soil will probably be
thin, and the subsoil layer will either be absent or scant, but more than
likely it was never used by a chemical storage facility by industry. While I
live in a large city, I was able to find 2 sites within walking distance of
my home which fit the bill.

The subsoil came from the base of a clay pit formerly used as a source of
clay used for bricks (Toronto Brickworks). While the Brickworks WAS used
industrially, it has two major advantages - it was one of the only parts of
the local area which was NOT pushed into the lake during the last Ice Age. 

(http://www.lostrivers.ca/points/BrickworksNorthwall.htm)

A careful observer can see the layering described in the above web-link in
the back wall of the quarry pit. I chose to use the Scarborough Formation
layer, deposited 116,000 - 105,000 years ago, well out of reach of
"industrial pollution". The Toronto area in those days was the delta in a
cold lake. Delta areas usually contain the ground up remains of rocks and
mineral laden soil washed down by the flow of a major river (in this case
the Laurentian River (long gone). This particular subsoil is a medium
neutral grey in color, accounting for its relatively low concentration of
Iron as recorded in Jamie Johnson's tests. I usually overcome this
"deficiency" by mixing in some Duplarit G, but only because I have a stock
of the stuff bought many years ago. Micronized Iron would probably work just
as well, as would Red Art Clay.

You need not go into as much research to pick a suitable soil to use, just
make sure that the area preferably contains native soil (not the trucked in
variety usually found in modern residential subdivisions, where the native
topsoil is removed before they put up the houses, replacing it with trucked
in material of uncertain origin. Again, it depends on where you live, and
the use the land was put prior to the building of your home.

The soaking IS important, but in your case you have no livestock in the tank
to be affected by any NH4 present. After about 3 months underwater, the
conversion of the NH4 into NO3 will be complete and no longer an issue.

I did add plain peat moss to the subsoil layer (per Steve Pushak's
recommendations on his website). I believe that Tom Barr recommends the
addition of mulm as a source of "good bacteria", and I think that is an
excellent idea for ANY substrate, if you have some. Tom's method obviously
works, and can jump start the necessary biological processes we want to
occur in a planted aquarium.

Don't sweat the details, use what you have on hand or can locate locally.
Experience will be your best teacher. Patience is a virtue every aquatic
gardener ought to have.

James Purchase
Toronto


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