Pressure Washing mildew UNDER YOUR HOUSE

About 3 years ago, I removed the chemicals I keep under the sink in the kitchen to clean that area & organize my chemicals (this but one place I keep them). I put plastic on my white ceramic tile kitchen floor to keep any chemicals from getting on the tile. Once I was finished, I noticed a small area on the tiles, where plastic WAS laid, that looked like someone had "splashed" or dropped something on the floor. NOPE, apparently one if the chemicals somehow got to the tile. The tile only has a very, very light glaze, so it isn't really noticeable (except to me). I bought a glaze from Lowes & used a huge sift sponge, & very carefully, & lightly used the sponge to apply a light coat to the dulled area. Once it dried, VOILA, it was back to normal. However, after a while, it came back again. I am sure with time & cleaning, it eventually gets cleaned away, like when we used to wax our floors. They no longer make that tile, the extras I had have been used already (I have a huge kitchen). I can continue to do that forever I suppose, but does any have a better idea. Maybe something that will last longer?

Any suggestions to clean pots like this? I’m able to get the sides clean but the bottom is proving a challenge. Are any of Ajax, Comet, Cameo, Barkeeper different from each other? Thx