I'm going out of town for a 2.5 days over xmus. I bought an auto feeder for the tank but no food for it yet. I feed the frozen green stuff that the guys at Trop. make so that can't be put in it. What food should I get that is safe for everyone in the tank....fish, shrimp, crabs, are all in the tank and it's a 90 gallon. I've read and been told that it needs to be free of copper.

Thanks

Joel