LS,
here in Aus, every fill I squirt lemon based dish detergent into the water bottle. I also run the tap full open. Not sure if I need to have it full open, but having the detergent reduce's build up on the blade (something I notice heqaps when sharpening time comes, I remove all the buildup off the tooth before sharpening and using the above I hardly get any build up on the tooth now) and the lemon base helps with the tanic acid we have in our hardwoods.
Might be different over there???