Like Mike said, it all depends on long the tank has been set up and what's in it (livestock).
Most places sell a cuc package that is oversized for a tank. You need to start small and grow your cuc as the bioload increases.
I prefer a clawless tank (snails and no crabs).
You may want to contact one our sponsors ReefCleaners
to see what he reccommends. He has a thread "We are Reef Cleaners
" where he is answering questions too.
I just got a package of 100 nassarius, 30 dwarf cerith, 3 fighting conch and a some macro algae as an annual booster for my 125.