I'm sure that a shower filter can remove some of the minerals, but I
question the practicality and expense of this kind of device. If your
water is really hard, you may need an entire house water softener for
your hot water.
Here's my tips...
1) Wipe down or squeegee (or use an after-shower spray) after every
2) Clean showerheads regularly with CLR, Limeaway, KaBoom or similar
product. If your showerhead is really clogged up you can soak it
overnight in vinegar or simmer the (metal) showerhead in a pot with 3
parts water one part vinegar for 15 minutes.
3) A shower liner will protect your shower curtain. Plus, you can
machine-wash most plastic liners with bleach to kill mold/mildew. Do
not put plastics in your dryer.