As we know, tiles will not fade, and neither can they tan in the sun. Tiles can, however, be affected by continual exposure to harsh acidic or alkaline cleaners. This is especially so in areas like a shower recess where cleaners are sprayed onto walls and left to pool on the shower floor. The reality is that tiles do not need these powerful and harmful cleaners. They can actually etch the glazed surface and simply make the tile more likely to trap dirt and grease and be harder to clean next time. These acids can also bleach the colour out of some glazes.
The other situation that can occur is that a film of soap and body fats can accumulate on a shower floor and dry to leave a white film. Each time the shower is used, the film builds up a little more. This occurs when the grout haze is not fully removed and polished off when the tiles are laid and the film attracts and grabs the soaps and fats. Then the tiles appear to be turning white.
All tiles, except specific industrial tiles are susceptible to acid or chemical attack. This is due to the prolonged use of unnecessary acidic or alkaline cleaners, especially in shower recess areas.
Otherwise, the build-up of body fats and soaps in showers can make a tile appear to fade. This usually starts when a film of grout is left on the tile at installation. This film grabs dirt and soap and builds up. It is accentuated when the shower is cleaned again with rinse-less cleaners that are sprayed on and wiped off. These leave a film behind each time that builds up over time. To test for this, try scrubbing a small area of the floor with just water added. If you can get suds to appear, that is the cause, and we can fix it easily.
If your tiles have been etched by acids, the only solution is to replace the damaged tiles. Then, only clean your tiles with warm water and a drop or two of disinfectant. If you really insist upon using cleaners, use Concentrated Tile Cleaner. This is ph neutral and low suds. Use Heavy Duty Tile and Grout Cleaner twice a year for a thorough scrub down.
If you believe that the discoloration is due to a build up of soaps etc., scub with Heavy Duty Tile and Grout Cleaner and rinse well. This should bring the tiles back to new.
From then on, warm water and a drop or two of disinfectant is all you will need. Alternatively, you can use Concentrated Tile Cleaner.