yes you can keep a cleaner shrimp without using RO water. I have a 45
high reef tank and I use city water. I have both a cleaner and a fire
shrimp. I plan on purchasing an RO unit but havent yet. I recomend
using amquell plus water conditioner for the clorine and cloramines it
also nullifies pheremones and will make your fish grow at a slightly
higher rate.