Haremahkeester

I'm trying to find a legitimate contractor that has experience with pressure washing limestone since we all know how porous this surface is. I have been told that using "safe restore" is the best chemical to use since it is a good cleaner/protector as well as it will not harm or discolor this particular surface. I have expensive landscaping around this 10 Yr. old house which is also why this product was recommended. Is this correct? Your input is appreciated