I have been dosing my plants with pmdd for less than a month and
noticed a strange thing: no matter how much I dosed, I could never
detect any iron. I always figured it was because my iron tester
(seachem) is VERY difficult to read at low levels (.1ppm). So
yesterday I did a test, I put 1 drop of pmdd into the cuvette used to
test iron and filled it up with blank water and tried to detect iron.
There was none detected. I then put in a small amount of the solid
trace element mix and dissolved that in the cuvette and still I
couldn't detect any iron. I got the materials to make the pmdd from
homegrown hydroponics. My guess is that the compound that they use to
chelate the trace elements binds stronger to the iron than the
material in the iron tester can bind to the iron. I was just
wondering if anyone else has experienced this problem, and how people
get around having such problems.

Jason Greene