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re: PMDD Dosing
>Jeff Bodin <bodin1 at gte_net> wrote:
>[snip]
>I currently have a 55g (about 50g water coulmn) and
>I am dosing PMDD. The iron test kit I have, I determined
>to be bad (no Fe levels, even when I dump the fertilizer I
>know to have iron directly into the test vial).
>[snip]
Without trying to be a chemist, I can tell you I have noted often that
PMDDs are often chelated with EDTA. Some of the popular test kits
will not measure iron chelated with EDTA.
I include the following message which I received from Sechem technical
support some time back regards their iron testing kit:
"Our iron kit will measure EDTA iron, but it takes
about 20 minutes as opposed to less than 2 minutes
for non-EDTA iron. The test kit has to have provison
for creating conditions in the test that will cause the
release of iron from the EDTA chelate before it can
be reacted with an indicator dye. Since EDTA is an
exceptionally strong chelator, this is not always easy or
reliable."
I think I am reading between the lines here that accurate EDTA
iron testing is difficult. I hope one of the chemists on the APD
could more accurately interpret this message and also, to indicate
if a more accurate test kit is available for EDTA iron.
Christopher Coleman
christopher.coleman at worldnet_att.net