Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws
Water's medium hard. Tap's a Crosswater - about 12 yrs old.
Reply to the thread, titled "Free up a seized monobloc spout" which is posted in UK Plumbers Forums on Plumbers Forums.
We recommend City Plumbing Supplies, BES, and Plumbing Superstore for all plumbing supplies.