Lignum Sulphonate as trace element chelator??

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?

Any info would certainly be appreciated.


in Ann Arbor where the rain showers are a sure indication that spring has
finally arrived!