Good luck! I live in the hard water capital of the world, and cleaning our plastic drinkwell is my absolute least favorite chore. You may run into similar problems with the motor in the 360, if it is the same design it can be pulled apart (the propellor is held in the casing by magnetics) and soaked and scrubbed with vinegar or clr to get that nasty scale off. Mine got so built up once it stopped pumping, but scrubbing fixed it.
"Here? It's like asking a bunch of rednecks which is better--Ford or Chevy?" ~Deltawave