You can add a cleaning crew now, if you've already added fish then you will start getting detritus build up without a cleaning crew. There are lots of different opinions out there about what constitutes the ideal cleaning crew, but it seems that most everyone agrees that the more variety the better. Definitely get a mix of snails (avoid margarita snails -- they are not well suited for reef tanks). The best snails in my opinion, are astraeas, nassarius, turbos (if you have algae), and conchs. You should add a brittle or serpent star in a little bit (they are more sensitive to water parameters) as they are excellent detritivores. You may want to add red legged or blue legged hermit crabs, but keep in mind they will kill your snails for your shells. I had hermits in the beginning, but got so sick of them killing things that I'd NEVER have hermits as part of my cleaner crew again. Emerald crabs are a good addition too, but they need algae to eat. As for shrimp, you should buy a cleaner shrimp once your parameters are stable for a while, or you can add some peppermint shrimp. But for now, a mix of snails should do a decent job. Be sure to add your cleaner crew slowly, if they can't keep up with the job, add a couple more. You don't want to add too many at once or they'll deplete the food supply and starve to death.