Generally most people wait for a rebuild until the vanes become worn to the point the vane falls out of the rotor slot. this This then busts the vane and jams the rotor from turning. Several features of the entire system will determine how fast the vanes wear out: operational hours, depth of diffuser, lack of proper air filtration, operation pressure.


aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management