Hello all...my first post

Just wondering what is the best product for filling the cracks in a Brussels driveway. My problem is the rain and general cleaning off the driveway causes a lot of the slag sand to disappear. I've heard of polymerized materials, but the color is tannish (is that a word?) and my pavers are gray and mahogany. My base is excellent, so I haven't had any serious movement of stones yet. Thanks in advance. BTW, I live near a Unilock plant, if their product is the best suggestion.
