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Re: Honey, where's my iron?

> From: "Aaron Ivers" <aivers at betamachinery_com>
> Subject: Questions about iron
> 1.  I understand that some chelated iron can be in the form of
> Fe++ or Fe+3.
> Can you tell the difference by its colour after being mixed in
> water?

Not certain but doubt it would be a good method:)

> 2.  If my chelated iron is Fe+3, is it useful?  Correct me if
> I'm wrong but
> I thought Fe+3 will only become biologically available only
> when reduced to
> Fe++ by the plant roots.

Yes, it's very useful. The plant's roots don't always do the
reducing, the bacteria do much of the work. Some plants can
extrude chemicals to release the iron/PO4 etc in the soils and
also to stimulate bacterial actions that will make these
available as a by product. Which plants? Don't know. Certainly
many of the ones we keep cannot do this. I recall a few can in
natural systems. Our tanks are not natural systems. It takes a
very low O2 to anaerobic place for this to happen. The insides
of porus grains are perhaps some of the best places and deep in
a gravel bed also are good for this to happen.
You can toss old nails in the bottom of your tank's gravel and
it'll work even. Iron filings/laterites are better. 

> 3.  If I mix EDTA chelated iron into PMDD with my moderately
> hard tap water
> (pH ~8.0), will the EDTA breakdown quickly?  Will the colour
> change, will I
> see rust in the bottom of the jar?

I don't do the PMDD. I go through 50$ worth of TMG in about 2
years. Just messing with the pmdd is not worth to me for the
small cost differences.
> 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?

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.
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.
> 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?

Too low.
> Maybe I should just switch to TMG and go out and buy a Hach
> iron kit...

It's easier but the iron kit is not a big issue. Seeing healthy
looking plants with deep rich colors, little algae presence,
decent macro nutrients levels, CO2 etc one can add more. Softer
water will require less trace mixes and not as rich waters to
achieve good growth. Harder waters can handle more iron/traces.
It won't hurt by doing this but might cost a bit more. A nice
kit is not a bad item and not wasted money in most cases. 
Tom Barr 
> Regards,
> Aaron Ivers

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