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Iron Levels

I want to question (in a most friendly and cordial way) one of the tenants
of the PMDD faithful:

Does Chelated Secondary Mix (from Plantex in Canada and the main ingredient
of PMDD) have too much iron in it?  Could 7% iron in a micronutrient mix
simply be too much iron for many of our planted aquariums?

My recent experience (say 6 months or so) has been that using enough PMDD
(made according to the Sears/Conlin recipe) to achieve 0.1 ppm iron levels
consistently results in hair algae and a darker brownish algae covering the
leaves of many of my plants, especially swords, anubias and h. difformis. 
Sometimes the algae has been quite severe, yet the iron levels remain below
0.1 ppm.  When I back off the PMDD dose to as little as 0.5 ml/day in my
125 gal. heavily planted tank and the iron readings settle in between 0.02
and 0.05 ppm, the algae situation is much improved and the plants continue
to grow well.

For fun, I recently did a large water change and switched over to Tropica
MasterGrow which contains only about 1/10th as much iron as PMDD.  As many
of you know, MasterGrow contains a mix of trace elements plus potassium.  I
have continue to supplement Epsom salts for Mg and to add K2NO3 to keep
nitrate levels at 2-5 ppm.  The initial results are quite encouraging: 
good plant growth and steadily improving algae situation.  

I don't know if I would go as far as Diana Walstad, but I'm thinking of
working on a new question:  Will my plants grow well (and without much
algae) if I maintain a "trace" of iron and adequate levels of other micro
and macro nutrients (excluding phosphates)?

I use both Hach and LaMotte iron test kits, and although I can't get them
to agree :-( I get both hair and a darker brownish algae if either kit
approaches 0.1 ppm.

I would be most interested in any of your thoughts or comments.

Regards, Steve Dixon