Something that may need to be cleared up is the terminology used. If I understand you correctly, you are dosing enough to raise your iron by .35 ppm
three times a week. That means that you are dosing 1.05 ppm
you could get away with dosing that .35ppm spread over the whole week.
That was never quite clear for me when I was trying to get started. I know that we accept the fact that macros dropping out can cause algae blooms. I believe that there are types of algae that seem to thrive on high iron. I base this only on reading and not actual testing.
Bottom line is I think you may be feeding more iron (micros) than you need to.