Well, I use about 50 lbs. every 2 months hand feeding right now and I am don't exactly have a supplier yet. I just get the catfish food that the local feed store carries and the blue gill have to do for now. They don't seem to mind.
I even feed the catfish in the pond, in front of my house (4 ac subdivision lake), cat food. It smells fishy and they love it. I just feed them for the fun of it.
I am shopping for a feeder, though, and will need to find a real fishfood supplier close by.