Moisture safety will maximize with supplemental coats, up to six coats or about a 20-mil thickness. Additives or pigments should not be added to the 1st coat. Mixing thinners with WEST SYSTEM epoxy is not proposed. You can use the “water drop” check to ascertain the cleanliness of your floor. http://industrialgradeepoxyfloor60369.blogolize.com/The-best-Side-of-clear-top-coat-epoxy-floor-29101998