There are many manufactures of sealers, from solvents to acrylic urethane. Epoxies, acrylic, and urethane sealers come in water-based versions and solvent-based versions, including combinations of both. The biggest difference between the two is the VOC content. The sheen and life of the product determines how often it lasts before needing to be reapplied. Solvent-based acrylics tend yellow overtime and don’t allow the concrete breathe. Epoxies are the strongest sealers, but are best used for smoother surfaces and more for indoor or warehouse floor application. The best sealers for paving stones are water-based urethane. They are algae and mold inhibitors, allow superior joint stabilization, they are environmentally safe, its UV Protection will not harm vegetation, and it is VOC Compliant in all 50 States. Well-trained Gappsi personnel can apply paving stone sealer products achieving the best results.