I cannot find a product to clean water spotting from my shower glass. Since my shower enclosure has a porous tile on the floor, I cannot use a product such as vinegar or CLR that would damage the sealant on the tile. I have used bar keep, scrubbing bubbles, Mr Clean eraser sponge, ammonia...but nothing eliminates the water spots. You cannot see the glass clearly in the attached photo. Any suggestions? HELP