the main advantage of 220 is the amp draw. you can run electric line a lot farther with smaller wire. cost is about the same in power use.with the aeration the motor will run a little cooler on 220, and last longer.as Pottsy said use a GCFI when near water. the problem with GCFI is moisture when installed outside. best to run GCFI breaker in panel box to the pond. as always talk to a qualified electrician before any wiring near water.
