So I have the BEST trick to getting hard water off of your faucets...Kaboom baby!!!!
Grab yourself a sandwich bag ( and a sandwich if you're hungry) and spray some Kaboom inside ( the bag, not the sandwich) Then just secure the bag onto your faucet with a rubber band!!!
Then leave it and do something else like eat a sandwich! ( I might be a little hungry right now ).
Every fifteen minutes or so pat the bottom of the bag just to swish things around. I usually leave mine on for at least an hour, then take it off and give it a little scrub and your faucet will look better than NEW!!! And it will work better too! I do this on my shower heads and sink sprays, it works GREAT!!!