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Re: Questions about iron

> From: "Jamie Johnson" <jjohnson at davisfloyd_com>
> Subject: Re: Questions about iron
> 
> Sometimes it depends 
> what kind of Fe+3 we're talking about ;-). Ferric chloride (FeCl3) is 
> made from ferrous chloride that has been reacted with Cl gas. It 
> registers as Fe2+ when tested. 

	FeCl3 _is_ iron III.  Which iron shows up when a test is used
depends heavily on the test method.

> > 4.  I assume the commonly recommend iron level of 0.1 ppm is for Fe++.  If
> > my Seachem iron kit measures Fe+3 and my trace mix is Fe+3 what should my
> > target level be?
> 
> I don't have a Seachem test kit, but if it measures Fe+3, then it 
> must chemically convert the ferrous to ferric before reading? 
> Sounds plausible.

	I think that Kevin Conlin and I were at least partly responsible
for the "0.1 ppm" idea.  We wanted to show that there was _some_ iron in
the aquarium water, and "just detectable" for the test we were using
at the time was allegedly 0.1 ppm. 
> 
> > 5.  My Seachem iron kit will not register any colour for at least four hours
> > and then gets darker the longer I leave it.  Evaporation becomes a problem.
> > The next morning it looks as though I have way too much iron, but only a
> > little amount of water is left in the cup.  What can I assume my iron level
> > to be?

	I would stopper the container.  Incidentally, if you are looking
_down_ through the liquid, and the container has constant horizontal area,
the change of path length as the liquid evaporates will make no difference
to the perceived colour intensity.  The liquid becomes more concentrated,
but the path lengths becomes shorter.

> From: Thomas Barr <tcbiii at yahoo_com>
> Subject: Re: Honey, where's my iron?
> 
> Where did this common 0.1ppm come from as some good recommeded
> level? I missed the boat. I add much much more iron than this.

	I think I was partly responsible.  One can indeed _add_
much more.  The point was not to have much left over.  I was trying
to avoid a buildup.

> You have other trace elements in there that are also used and
> having a low iron level as a base line also has the rest of
> these traces at low levels also. In a fast growing tank this
> level goes to zero and is used up. I think many folks starve
> their plants in effort to control algae. A weak plant cannot use
> up the nutrient like a strong plant. It's a weaker competitor
> against algae.

	Agreed.


-- 
Paul Sears        Ottawa, Canada