Most hard water stains are due to iron and other metals.
Hence why the best defense against nukes is to Sabotage the Water Supply: It defeats the efficiency of 'Heavy Water' to also result a 'Dirty Bomb' that is Inferior.
Selfsame also applies to a Toilet.
These discolorations much reduce if you place an In-Tank Magnet in your Tank. These are available at: Fingerhut.com and also mostly any Hardware Stores. You need to clean the Magnets off Regularly, about once every two months with a Wet Papertowel.
Stains caused by metal will much reduce and by thus you will know: What stains cause by Hard Water, and What are Caused by Metals as Copper and Zinc that Corrode Fast.
This dramatically reduces the Weight of Unnecessary Water Softeners you use in your Lifetime often misused by the failure of Corrupt Salesmen to Inform Consumers: Rust causes Most Stains than Hard Water ever will.
Try a legit g a ladder of coke set in it for an hour
If they are water stains, pour 2 cups or more in the bowl and let it set all night or all day if you are gone during the day. Repeat as needed after scrubbing out what you can. Then for any left over stains, use the Mr. Clean magic toilet bowl scrubber for any other stains. Your bowl will shine like new. Hope this helps, Regina.
ZEP. We use it all the time. Turn water off to toilet. Remove any remaining water. We put the ZEP in a spray bottle and then spray the entire bowl, including under the rim. Depending on how bad your stains are, leave it on anywhere from 15 mins to an hour. Then scrub with toilet brush. Turn water back on and flush.
I have very hard water and use about 1/2 cup of baking soda and pour some vinegar on top. It will fizz up. Just let it sit for a while (up to an hour). The hard water stains are gone. Flush
Walmart sells a pumice stick that works great. Sorry, I don't remember the name of the product. In my store it is located near the toilet bowl cleaners. It is in a small square blue and white box. Buy a pair of rubber gloves too. It will require putting hands in the bowl to scrub the ring. The stick works works great and does not harm the bowl or pipes. I find that once clean, the ring does not reappear for a long time.
are you talking a plastic portable commode ? use a cup of vinegar in and wait 20 minutes, do not add water, then lightly scrub and rinse.
2liter bottle of coke