I've come to the mind that the best way to insure long term iron
supplies is to put it in your substrate right off the bat. I've tried
peat and don't much like it in the substrate, bare gravel with root
tablets, and Tetra's Hilena Initial Sticks. I've had good results with
all but the peat. I was thinking about using the Duplarit G product in
my 70, but this stuff is really EXPENSIVE.
I also picked up a cheap little Tetra CO2 diffuser and a small bottle of
CO2. My water's pretty hard here, but thought I would give it try
anyway. A friend of mine has this same minimal setup and gets
noticeably better plant growth than I do with only a very slight change
in pH. $45.00 seems a good investment if it works.