Buy a skimmer that cost you $350-500 for that tank. Why? because if you buy a cheap skimmer, like a coralife, or red sea prizm you will waste the money and get a new one.
Popular brands are deltec,euroreef, mrc, octopus,precision marine.
O yea and get a refractometer from the start! Dont use the swing are hydrometers they SUCK! EX: the salt will read 1.026(nsw) but really the salt is 1.030 because of temperature. A properly calibrated refractometer will not be prone to inaccuracy like that. O yea and make sure it is ATC(automatic temperature compensation)