This may sound too good to be true, but I tried it and it worked wonders on the tile in my shower. Clorox bleached diluted with water. About 2 parts bleach and 1 part water. Spray it on the tile and allow it to sit for about 15 minutes. Then rinse with water and wipe clean with a damp towel. Hope it works for you!
What I have found works best is white vinegar in a spray bottle. I don't dilute it with water if the deposits are heavy. Spray and let sit long enough to penetrate the stains and then wipe with the rough side of a sponge. You may have to make more than one attempt. Rinse with water. Then, immediately go to Lowe's and purchase Method Shower Spray. Spray this in your shower area after every other use of the shower. Just spray on and leave it. I haven't had to deal with any cleaning of deposits or soap scum since! Hope this helps.