UV sterilizers are generally not worth getting. For your 110gal, a minimum sized UV IMO would be a 30-watt model. For that size and price, you're much better off spending the hundreds of dollars on getting a better skimmer, adding a refugium/turf scrubber, and so on. The only benefit to a UV is that they tend to help with water clarity. They have no impact on diseases for fish and coral, nor will they help remove hair algae or cyano.
To the contrary of popular opinion, UV's have zero side-effects to your tank, other then a minute amount of heat, and of course price/hole in your wallet. At the proper flow rate, they have zero effect on pod population levels and does not affect the "good" bacteria in your tank.
