Removing rust stain from acrylic shower

I have recently found out that I can remove stubborn rust stains from my acrylic shower by using cheap baking soda like cleanser and spray it with lemon juice ( the kind in the bottle) It will foam up and with continued scrubbing it WILL come clean. I also tried using a product from Whink that is to protect the clean surface by providing a surface that is supposed to keep it from staining. I did not have much success with that. After one week the stain returned. The problem is a dripping hand held shower fixture. I have tried everything to make it stop dripping but with NO success. But I am pleased that the baking soda and lemon juice is a wonderful fix for all of the rust stains.