The biggest issue in dealing with mold in a tile and grout shower, is that you can’t use the typical aggressive products designed for killing mold because they kill your grout and often metal as well.  Tile showers are durable and easier to care for than natural stone showers.  Keeping them looking that way means that you must be very careful with the products you use, so that you don’t actually cause damage to your grout and other surfaces.

Mold likes to live in a dark, warm, moist environment with an ample food source of organic material.  This makes a shower a nearly ideal spot for mold to grow.  The small pores of natural grout are great places for mold to live and avoid your cleaning efforts.  Most products used to eliminate mold only remove the surface mold and not the mold still doing well inside the pores.  Ironically, many mold cleaners say that they are not to be used on porous surfaces, which explains your frustration in why mold never seems to leave, or not for very long.

To effectively remove the mold stains from your tile shower, you need a product that is both safe for your grout and able to penetrate into the pores of the grout to remove the visible and hidden mold stains at the source.