Our tile guy said to not use anything but water to clean the tiled areas until the grout was sealed, because chemicals in various cleaners can permanently discolor the grout. Is there any truth to this? I'd swear I answered this, but I guess not! It sucks getting old! Your installer is right in that many CAN hurt the grout color. He's also right in that water should be all you NEED to clean it. But if you DO need something more than water, mix up some Oxyclean. It'll do just as good a job as chlorine bleach without hurting the grout the way bleach will. Does tumbled marble tile need to be sealed? We have tumbled marble 3x6 subways for a border and accent tiles in the master shower and tub deck, and 1x2 mesh on the shower floor. Our kitchen backsplash is also tumbled marble. If we should seal that, what is a good brand and what method is best to apply it? Although I don't believe in sealing grout, I DO believe in sealing stone. Two good recommendations would be Miracle 511 Impregnator, and Stone Tech Impregnator Pro. Both would be applied in the same manor-- take an old terrycloth towel, and rip it in half. Use one as the applicator, and the other, to wipe off the excess. Take the applicator, and wipe a liberal amount of sealer on, let it set for about 5 minutes or so, and then take the dry half and buff off the excess. Done. I just had my new bathroom tiled and my contractor (NYC area) did not recommend it. His bathroom and kitchen are not sealed. I think (but am not positive) that he also said that sealing was another way to make money and that once sealing is done it has to be done again in the future. With respect to sealing the grout, I agree with him 100%, including the part about it being a racket.

"Sealers Choice Gold" is one of many good ones. "Stonetech" also has good products. I'm not enthused about "TileLab" frome Home Depot, but others might disagree. You won't need much, but avoid the cheap products. Easy way is to pour some into a small plastic or foil dish. Apply with a disposable, foam rubber brush...about 1 1/2" ones work pretty well. Buff any excess off the tile with a towell.

Posting for updates as I'm making the same decision right now. Our penny tile is on the floor in a kids' bathroom, so we need something that is durable. Our tile installer has recommended Custom's Pro Fusion in Bright White.

This is a seminar and I won't go into that kind of breadth or depth on this subject. Basically, four things to consider regarding sealant: 1) use of the space - high traffic?; 2) color of grout; 3) type of grout; 4) type of sealer. Most sealers are not impenetrable and do breathe. Their purpose is to aid in the cleaning, not to make cleaning unnecessary. I would not rely on HGTV (both of your sources were actually quoting some HGTV guy) and a carpet cleaning company for information on this. If you get a room full of real professionals together who have been doing this work for decades, I'm doubtful you will find agreement with your referred sources conclusions. Seal on but rely on manufacturer recommendations and those of your qualified tile professional to determine the best sealer (and grout) for your application. Now, from afar and in general terms, your question about a non-sanded grout sealer. Have you already grouted it? If you haven't, then Laticrete Select non-sanded grout does not require sealant. If you have already grouted it, then we might recommend Miracle Porous Plus (use it in well ventilated area as it is petroleum based). Van Herron Stain Guard is fine too (do a couple coats if you use that). Our opinion but we base these decisions on all the things mentioned above on our own projects. I just realized that you changed your post and my response is based on the previous post you had up.