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RE: Seachem Iron kit - spoon capacity



Greg

Thank's for the prompt reply.  Yes, I know the spoon's for the reagent
powder really - I'll try to engage brain before hitting keyboard next time!!

I mixed up my first batch of PMDD at the weekend & made up some reference
samples (0ppm, 0.1ppm, 0.5ppm, 1ppm, 10ppm, 100ppm) to try to get a feeling
for how well the Seachem & Red Sea Iron test kit (which I also have) would
detect the chelated (EDTA) Iron in my trace nutrient mixture; 'TE Mag' from
Solufeed (a UK company) containing 10% Fe.

The results are kind of interesting...

Both the Seachem & Red Sea kits detect the Iron in the Seachem reference
sample almost immediately.  The Red Sea kit indicates 0.1ppm when no Iron or
0.1ppm Iron is present, somewhere between 0.1ppm & 0.5ppm when 0.5ppm is
present & 1ppm when 1ppm is present.  I found the Seachem kit almost
impossible to read at levels below 0.5ppm because the reagent makes the
water yellow.  Above 0.5ppm the purple becomes dominant & at 1ppm it was
pretty accurate.  Unfortunately I'm trying to detect levels around 0.1ppm so
I don't think the Seachem kit will be that useful (other than detecting the
qualitative difference between 'no Iron' & 'some Iron').

Which is a shame because the Seachem kit accurately detects the chelated
Iron in my PMDD very efficiently (within 20 - 40 minutes) whereas the Red
Sea kit is pretty insensitive; after 2 hours the Red Sea kit gave a reading
of 1ppm when the sample contained 100ppm Iron & at 10ppm & below the Red Sea
kit reads 0.1ppm (which is actually the base colour even with no Iron
present).  At 1ppm the Seachem kit gave the correct reading but below this,
again, it's hard to get a useful reading because of the yellow colour.

Why does the Seachem reagent make the water yellow?  I followed the
instructions (they're not hard!) but maybe I'm doing something wrong?

Best regards - Kevin

-----Original Message-----
From: Greg Morin [mailto:greg at seachem_com]
Sent: 29 November 1999 18:11
To: Aquatic-Plants at actwin_com
Cc: Buckley, Kevin
Subject: Re: Seachem Iron kit - spoon capacity


>
>I recently bought the Seachem Iron test kit & it contains a handy looking
>spoon for mixing up the reference Iron sample.


The spoon is for the reagent powder...not making the reference ;-)


>
>Does anyone know the spoon capacity in ml (or grams, as I guess most
>'powders' of this type have an SG of around 2.0 - 2.5)?  It looks like
>around 0.2ml.
>
>Maybe Greg Morin knows if he's listening?


The spoon holds approximately 100 ÁL (0.1 mL)

-Greg Morin


Gregory Morin, Ph.D.  ~~~~~~~Research Director~~~~~~~~~~~~~~
Seachem Laboratories, Inc.      www.seachem.com     888-SEACHEM
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~