Stonetech Bulletproof sealer - used to be owned by DuPont but I think is owned by Laticrete. I received many recommendations for it over on John Bridge Tile Forum.

Any sealer out of a can will only protect marble from staining, not etching. The best way to protect marble from etching is with More Anti Etch which is not a DIY project. Plastic films such as Tuffskin will prevent etching as well, but are not DIY either.

This is a new installion of a bathroom. are you saying any sealer to be applied ? Does marble in a bathroom become etched? i know counters in kitchens do.

From my experience, marble does etch in bathrooms from the water. And it also etches from even resting some cleaning bottles on it while you or your house cleaners are tidying up. Those are the deepest etched. The water ones don’t bother me but the outlines of the bottles are more noticeable.

I agree with Joe about using any sealer.

Are you asking about a marble bathroom vanity counter - OR - will marble be used inside a shower?

Water can cause marble to etch on a bathroom countertop. I have a polished marble counter in one of my bathrooms - and it has just a couple etch marks. No one really notices them - except for me if I look for them.

Now - using a sealer inside a shower is a debatable topic. An impregnating sealer will help some with stains (but have zero effect on etching as has already been explained above). The pros over on John Bridge Tile Forum (as well as some other pros who specialize in marble) believe that you should not seal marble inside of a shower. The issue is that an impregnating sealer will allow water vapor to enter the stone (along with water entering the stone through grout lines) - and once it changes back into its liquid state, it can become trapped inside of the stone (and take quite awhile to dry out).

Sealers do not waterproof or protect from etching. Plastic wrap isn't a solution in a wet area either. When choosing marble in a bath, you are choosing the potential for issues. You picked what you picked, and the decision has consequences.

I have found a good sealer. my previous bath is all marble and with regular sealing (twice a year) has not changed color or etched in 10 years. Hopefully the next bathrooms will be the same. Thank you everyone.