Bad Tile Scale: Advice Needed

[labboy]

Hi Everyone:
We have a fountain in our courtyard lined with nice decorative tile. The tiles on the floor of the fountain have developed bad tile scale over the years. (The attached photo shows the tiles on the bottom and the same tiles on the side with less scale.)

Any suggestions for cleaning the tile? I've already tried citric acid based tile cleaner (6%) with little effect. I am hesitant to use something as strong as CLR or Lime-A-Way for fear of damaging the tiles. I was thinking of making a large batch of citric acid (with some STPP added) and filling the bottom of the fountain with about an inch of it and letting it sit for a few hours with periodic brushing.

Any other suggestions?

Thanks
Bob

 

[joelippard]

Others here who know more about chemicals than I do may provide better suggestions but one thing I would try that is safe to use is 20 mule team borax.  I have been able to clean all manner of nasty things up with that stuff.  Just wet the surface lightly and make a paste like substance with the powdered borax, scrub and then rinse thoroughly.

 

[gansky1]

Beautiful tile! There should be some products at your local janitorial supply that will do a good job removing the scale. Give them a call and you'll have an answer in short order. There, you'll be able to get a higher acid concentration solution that will be fairly quick-acting and easier to work with. Wear gloves and eye protection.

 

[rockland1]

I would talk to someone at a pool store.

 

[whirlcool]

Have you tried a pressure washer?

We had some friends who had a tiled patio that kept getting covered with mildew and calcium stains. They used a pressure washer to keep it clean.