|not my tub photo source|
Hydrogen peroxide in a spray bottle (I bought it this way from walmart, then refill it from a big bottle as it needs to stay in a dark container, but you can take a sprayer from an old bottle and fit it on the top of a regular bottle of HCO3)
Vinegar in a spray bottle.(**do not mix them together in one bottle as they are more effective sprayed separately**)
Spray your tub with the Hydrogen Peroxide. Then, spray the tub with the Vinegar. You can let it set for a bit, or wipe away. I use a scrubby on areas where soap residue and hard water are the worst within a minute.
Just that simple. We have very very very hard water. I use the Vinegar on the chrome fixtures and they gleam. And I have a nice shiny clean tub.
Linking up Jill's Home Remedies and Here at Like a Mustard Seed