Careful Dosing Flourish

My first experience of the delicate equilibrium of fertilization - I dosed 5ml of flourish for the second time in a week (as per the fert. sticky) and overnight I got tons of hair algea growing everywhere. On chucks planted aquarium he said it's because of excess iron. Just thought I'd share my experience - BTW will my farlowellas eat this stuff?

I have 2 bunches of wisteria, 2 large bunches of rotalla indica, 6 bunches of tropical sunset hygro, 2 bunches of scarlet temple, 4 bunches of bacopa carolina, 3 bronze wendedti's, 3 anubias nana's, 6 java ferns, 4 bana plans, 2 compact swords, and 2 melon swords. The entire back wall of my tank (5ft) is covered densly with stem plants.