Re: Aquatic Plants Digest V2 #27

Steve Robertson <svr at eecs_umich.edu> wrote, Mon, Apr 22:

>Here's a question for all of the chemists on the list.  In my attempts to
>come up with some ingredients suitable for mixing my own PMDD, I came
>across a liquid chelated iron mix.  It seems to have all of the trace
>elements in about the same proportions as recommended by Conlin and Sears,
>but it uses a chelating agent that I am unfamiliar with.  I believe it is
>called Lignum Sulphonate (I don't have the bottle with me today) and I was
>hoping someone could enlighten me.  I realize that the EDTA/DPTA chelators
>are considered the best, and are also known to be safe for the aquarium.
>Does anyone have any experience with Lignum Sulphonate?  Is it effective?
>Are there any known toxic properites that could be harmful to fish or
>aquatic plants?

All of the garden stores in this area that I have visited carry fertilizers
and other garden products made by Fertilome.  They sell bottles of a liquid
iron supplement, and, about 10 years ago, I bought some.  As I recall, it
claimed to have its iron chelated by lignum something-or-other.  I didn't
think that the chelation was very good, because, when I poured a few cc in
one of my tanks, I immediately got a cloudy precipitate.  A year or two
ater, most of the iron salts had precipitated out in the bottle.  Just a
few days ago, I looked at another bottle on the shelf in a garden store of
their iron supplement, and I noticed that now they have their iron chelated
with EDTA.

Paul Krombholz                  Tougaloo College, Tougaloo, MS  39174
In already humid Mississippi