Re: Aquatic Plants Digest V1 #170

> Just a wild guess, but maybe the DUPLA product contains a sodium salt
> of EDTA instead of Fe:EDTA, Mn:EDTA etc., i.e. metals already chelated.
> I think that Allgayer and Teton mention this method in their book.
> Another reason not to use DUPLA?

	If I remember my chemistry correctly (and I may not), even after
EDTA has chelated an ion, it still has a negative charge.  So, while the
EDTA is holding Fe, the sodium could be just "hanging out" neutralizing
the charge of EDTA. 

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