QUESTIONI recently allowed a phosphoric acid based cleaner to set on my pool tiles a little too long while cleaning the calcium deposits. The acid etched the overall glaze and created some drip etchings as well. Might you recommend any product that would mask the dull etching effect, and that might also withstand immersion in pool water? Many many thanks for any insight you may provide.
ANSWERAnswer - Unfortunately when you acid etch the surface of a glazed tile it chemically alters the glaze and it can't be restored.
If the etched area is contrasting in color to the tile color, you could try to stain over it with an epoxy based grout colorant. You have to experiment to see if it works to your satisfaction so test it out first.
The best thing to use to remove calcium build up is a pumice stone. It is soft but abrasive. best to clean the tile on a regular basis before it gets too bad and requires more effort to remove.