CLR is a hell of a chemical if you let it sit. The thing is, let it sit too long it will take your grout right with it.

That’s more than a hard water issue. That’s a red flag to look deeper at a failing shower.

I have posted about this product dozens of times, I think, but it is so great!!! You can send for a free sample (where it says 1 oz pouch for $0.00, or my local Ace Hardware sometimes has free samples (that's how I found it originally). I have only used the cream in a jar; they also have a liquid in a bottle that I cannot vouch for. It is gentle and non toxic, smells great and cleans everything from tile to windows to fixtures, fiberglass, the plastic parts of shower appliances, etc. I found out just coincidentally, that my window guy uses it on the water spots on my windows.There is another Bioclean company that doesn't have a hypen in the name, so don't get that one...(or at least I can't vouch for it).

https://www.bio-cleanproducts.com/

consider ethics when selling, look into latex leaching and efflorescense.