I have a real hard time winning money from the 20/5, 30/10, 40/5... limp call preflop guys. I raise to isolate, but they don't fold and I have a hard time pushing them around postflop. I never seem to know where I am with these guys. I am looking for suggestions to help with this. I am thinking about raising more preflop when I have position(maybe 5x or 6x). I think this will help further my isolation, 'cause everyone else plays with the fishes too, and lowers their odds/ makes me get paid easier with TPTK type hands. Is my theory here flawed, and what other things should I do to get the $$?