mold removal from tumbled tavertine bathroom tile?

Hi! Our bathroom walls are white, porus, tavertine (tumbled). Bad us, we didn’t seal it properly…now thanks to the moisture from the shower mold is growing in the stone. We’ve tried traditional mold-remover (damprid), bleach, and scrubbing without sucess. Can anyone recommend a really strong product, or someone expert at dealing with mold removal? The stone is beautiful, and we don’t want to lose it. Thank you!

By svaxelrod |