Okay, so adding bloodmeal to your system raises iron levels and also nitrogen.
I bought the Miracle Gro Organic Choice
http://www.homedepot.com/h_d1/N-5yc1v/R ... reId=10051
It has 12% nitrogen which I could use about now. The problem is.... it is insoluble.
I added about a tablespoon to each grow bed near the water inlet and buried it about an inch down. I guess the nitrifying microbes will break it down and make it available to the plants?
It doesn't mention iron on the label but I imagine that since it is bloodmeal that it's a given that it contains iron.