So, I just had new leathered marble pavers installed on sand over an existing concrete deck in Florida. Right now there is no sand between the pavers (in the joints). I commonly hear that polymeric sand is the way to go and that the only downside is the cost and was about to install that when an industry pro told me not to use any sand because it is unnecessary and may actually cause issues with locking moisture in. Another pro told me to use regular sand because, while the polymeric forms a nice barrier, it flakes and chips over time and you can't just add more sand to it so it becomes a real pain in the butt. I would really love to know what your experiences are with this if you have marble pavers. Again, mine are leathered marble, not travertine. As a bonus, if you can give any feedback on the type of coating or sealer you may have used, that would be fantastic.