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Re: Iron adn TMG etc
Roger Miller worte:
"What a load of typing, James! I have a few comments."
What can I say.....it was a slow night on TV and I had nothing better to do.
Actually, you had said that you didn't have a copy of The Optimum Aquarium
and it would be kind of pointless to conduct any sort of conversation if you
didn't know at least what was written there. I added the Allgayer & Teton
material because it seemed related and I know that the book is not widely
known or owned.
"...As a result in many areas where plants grow along
streams their roots are provided with a constantly-renewed nutrient bath.
Some of the nutrients make it on into the water column and for the most
part they are rapidly precipitated."
That plays along with Dupla's observations that at least in nature, the
nutritional needs of plants can be met by constantly recharged sources which
are low in concentration.
"Most natural water has iron levels in the range of a few parts per
billion. "Black water" from marshy areas can have iron content over 5
Go check what is on the Dupla website regarding tannins - I asked them
several questions about tannins in natural systems a few years ago and they
had an expert answer my questions. Unfortunately, the answers were not those
I was hoping to get......but that's life....
"Could the authors have meant micrograms/liter instead of mg/l?"
I suppose that it COULD be a typo, but it does say in the book "mg/l". If it
was an isolated typo, it would only occur once or twice - this level is
consistently reported. It might have been the result of an over enthusiastic
editor I suppose....does anyone know of any other sources for these sorts of
recommendations? The original book WAS written in French, and maybe their
concept of the metric system is different. I only read English and I would
expect that any material of this vintage would have come out of Germany or
another EU country.
I am aware of what you say about recommeded iron levels in potable water --
it seemed odd to me when I read it.
"The highest iron contents I've seen in surface waters have been a
few mg/l in very soft water from marshy areas."
Was this observation made in a tropical country with a laterite rich soil?
I don't have any quantitative measurements at hand, but when I was growing
up in northern Nova Scotia I often observed rusty red sediments in shallow
ponds surrounded by sphagnum bogs. Where there was solid ground as a
substrate, there were many very healthy aquatic plants, mainly Sagittaria,
Sparganium, Nuphar, Rumex, Potamogeton, Ultricularia and Elodea. The iron
oxide might have been caused by the presence of large amounts of mine
trailings (from the numerous coal mines in the area). The basic overlying
geology in the area was full of limestone, so the water was anything but
"soft". At the time (this is over 25 years ago), I didn't even know what an
essential element was, let alone how to test for it.
"The little bit of summary material I have includes a nice
little summary of iron chemistry and occurence, but *no* justification for
the 1.0 mg/l standard"
Other than Allgayer & Teton, Tom is the only reference I have which would
indicate that this level of Iron is beneficial. Given his enthusiasm for his
approach, and his obvious success with it, I am not prepared to dismiss it
out of hand. But I think that there is more to it than JUST an elevated iron
level. He has found a "sweet spot" in his own tanks which works for him.
Every aquatic gardener who hopes to achieve long term success has to find
their own "sweet spot" based on their own conditions and expectations.
I would love for Tom to say where he got the "aim point" - was it based upon
Claus Christensen's suggestions or upon some research paper he may have
In my own tanks, given the way I prefer to run them, if I added this level
of micronutrients I would run into major problems with algae. That could be
due to the fact that I would have to learn the necessary levels of other
nutrients needed to balance things out. No one nutrient can be looked at in
isolation - the whole picture has to be considered.