How to remove mineral ring from toilet bowl

http://homeguides.sfgate.com/remove-calcification-toilets-43063.html

at your local hardware store they sell a square pumice stone it works fantastic and will not hurt the porcelain finish or enamel finish on your toilet or sink

Drain water and gently use a pumice stone

I pour about 1/3 box of baking soda into the toilet and a few squirts of dish washing liquid. Then I pour some vinegar in the toilet. Let it foam up, swish around with a toilet brush to suds it up. The suds suspends the vinegar abouve the water line. Let it sit for about one to two hours. Swish around with the toilet brush again and flush.

An environmentally friendly solution might be a vinegar solution. "Clean and deodorize your toilet bowl by pouring undiluted white vinegar into it. Let stand for five minutes, then flush. Spray stubborn stains with white vinegar, then scrub vigorously." See: www.almanac.com/content/household-uses-vinegar

CLR (calcium, lime, rust removal) has been around awhile.

try coke!

WD40, white vinegar.

Obviously clorox didn't help. You might try a product called CLR , it does a good job on calcium deposits, make sure it is ok for the bowl enamel.

An energetic scrub with Bartender's Friend (I think that is the name) might help.

WD40

pumice stone is the easiest way. Be sure to keep it wet so it doesn't scratch the porcelain.

Lime Away works great! I have the world's worst water that is full of calcium & leaves a crust coating on everything it touches. Lime Away is the only thing I have found that works with my problem. I tried CLR & several other cleaners, but none of them worked. I think you will like the results of Lime Away.

Vinegar or bleach in the tank of the toilet. don't let the vinegar in too long.

try Lava hand soap--it has volcanic ash in it which is used to clean plumbing fixtures!!!