I just thought I would post an update in case it helps anyone. I had e-mailed General Hydroponics with the same exact question and there response was:
I think the only difference is the concentration. Food grade is 10 times stronger. It is also ten times more expensive.
I am not concerned with the concentration because I won't be using that much to go to the time and effort of finding a source for the 35% concentration. One bottle of the 3% from walmart for $1.06 will probably last 6 months. If not whats another $1.06.