Hmmmm logic wise, I think you should have downplayed your sand layer by quite a bit (should have replaced it with some larger rock textures). You don't really find all that much sand in tide pools, unless it's trapped within the tidepools themselves. (or atleast the ones I've seen).
Also would have gotten rid of the tiretrack addition, doesn't really make sense for anyone to be driving over tidepools to begin with (a quick way to ruin your tires, and destroy an ecosystem!)