Honed will be less obvious. If it's etching, sealer or honing won't prevent it. I'd question whether it's just water, and what is in whatever you're mopping it with, too. (I only clean the marble with marble cleaner.) My only spots are around the toilet... Nothing to prevent that short of sitting. This post was edited by KevinMP on Wed, Apr 24, 13 at 23:04

We have marble border stripes on the tub surround in our MB, and split face travertine border tile on the tub surround in our hall bathroom. Been using 7th Generation Disinfecting Bathroom Cleaner (spray). I spray it on, let sit a few min., and then wipe dry with a microfiber cloth (no rinsing necessary). I usually spray some on the microfiber cloth before wiping in order to help spread it around on the tile and grout lines. We also spray Mrs. Meyer's Shower Cleaner (the daily spray) after showering. I called both companies to make sure those products were natural stone-safe. Some others from both lines are not. I use Marbalex (from SCI) mixed with water for mopping all of our floor tile--travertine and porcelain. It's a no-rinse stone-safe floor cleaner. I don't know if it disinfects, but we are fine with just using soapy water to clean our floors.

I have marble tiles in my shower and there isn't a vent or fan. However there is a window and after a shower I quickly squeegee the walls and floor to remove excess water and then leave the door open. It only takes a minute to do because its a small shower. My tiles are light gray, matte finish with a lot of veining so the dirt doesn't show right away, but I try to look for it and scrub it with a brush as soon as I see dirt. Then I am careful to use only baking soda/hydrogen peroxide. If the grout needs a deeper cleaning, I steam it with a Bissel home steamer maybe 2x per year. So far, the tiles/grout look great and its been 2 years. I think the trick is to catch it early and don't let water sit. So its a little extra effort when getting out of the shower but it eliminates having to scrub a lot longer once a week and it always looks clean. And I will reseal every year. That makes it a lot easier to clean the grout too.

We are redoing our bathroom using wall-to-wall marble tile, specifically China Black if that makes a difference but anyhow. I was advised by my contractor that marble on a shower floor is highly susceptible to staining/spotting/scaling from hard water left to dry on the surface. One option obviously is to dry the marble each time a shower is taken, but this is intended to be offered as an upscale rental eventually, and as such do not trust guests to do this. Instead, I am trying to find a water treatment solution which will eliminate any calcium, manganese or iron that might cause this effect to begin with. I live in Southern California, where the water isn't great but also not horrible, and have a traditional salt-based water softener already. I've looked at straight up filters which claim to remove iron, calcium or manganese, but was told these are intended for removing suspended particles in the water, where what I described would be considered "dissolved solids" and would need a different solution for hard water specifically. (This is what I first was looking at: Filter) I then looked at this from Nuvo H20. We had a solar-panel cleaning system installed, and the vendor said they recommended a similar product from Nuvo installed along side that system, even though we had a traditional water softener already. They claimed this product would help ensure no scale or crust build up on the panels. The reviews I read were somewhat mixed however, and am not confident this is what I need either. Can someone provide any advise on what sort of water treatment solution would help protect my black marble shower from spotting/staining? I want to be able to leave the tiles wet without any damage, so need something that is very effective, but that can provide about 5 GPM of water flow. I had looked at RO systems, but those which can deliver that require an electric pump and gigantic holding tank.