(that means your water has a lot of minerals in it — if you get
soap scum easily in your bathtub then your water is hard), try adding some Calgon Water Softener, RLR, or TSP (tri-sodium-phosphate).
You have an idea of the harsh chemicals they often contain so they're able to remove
soap scum, disinfect surfaces and restore the shine of your hardwood floor as
easily as possible.