Hook won't set when Cat/Carp Fishing?

I lately have been fishing for catfish and carp at the pond near my house. I have been using hotdogs and Gamakatsu Circle Hooks and have been trying to conceal the hook. I have been using about 1.5 inch hot dog slices on a 1/0 gamakatsu hook. When the i see my rod tip bend, i go over to my rod holder pick up my rod and the fish seems to spit it, i sometimes can't even set it.