What if none of this works? I get orange stains even with correct use of water softener, and cannot afford professional cleaner.

The best product I've found to remove rust (the orange stains) or calcium from a shower or tub is Extra strength scrubbing bubbles. Don't get the spray can, but the trigger spray bottle. Spray it on, leave it sit for a few minutes, then take a scrub brush to it and rinse it off. If this or a couple of applications of this don't work, then take some muriatic acid (available at hardware store). Dilute the acid - 1 cup acid to 5 parts water. Using a brush to apply and scrub in all directions. Be sure to use rubber gloves and safety glasses.