For extreme hard water stains, Pour a little baking soda on the tough spots first, let it sit for 5 mins and rinse before doing this remedy. Fill a spray bottle 1/2 full with vinegar. Add 1/4 cup lemon juice. Fill the remaining space in spray bottle with soap of choice. Shake up that bottle and soak those stubborn stains baby. Let sit for 30 mins. Time to scrub that grime away.
FINALLY found the REAL secret to cleaning hard water spots off glass shower doors!!! I've tried every product you can buy and mixed up every Pinterest recipe I could find. Nothing ever even touched the stains. The secret is simple. GLASS TOP STOVE CLEANER!!! Use the applicator pad that it comes with, follow the directions on the bottle, and that's it!!! You're welcome!!! :)