We have a Mexican tile deck all around our swimming pool. It is developing a whitish cast to it. Can this be cleaned and with what?

This white cast is very common with Mexican tile. Hard water and chlorine from your swimming pool are depositing a white salt on the surface. To remove this white haze, a mild acid washing is necessary. Use a mild acid such as sulfamic acid (available at most home centers or tile supply stores). Mix the acid solution and apply it to the tile. Scrub with a soft, brittle brush and rinse thoroughly. Be sure to follow label directions carefully. Acids can be difficult to work with, and can cause damage to other surfaces, such as metal. If in doubt, hire a professional to do the job.

TIP To prevent this whitish haze from returning you may want to apply a good silicone sealer to the tile.