My builder sealed our flagstone coping and decking with a gloss sealer. It had the "wet" look and looked great for about six months. It started to fade and they came back and did it again free. The product they used was called "Diamond Super Clear" I think. It's only sold at masonry stores and is about $50/gallon. Now eight months later, it needs it again. The pool is in full sun most of the day. Is there a sealer that will give us the wet look and last longer? I live is S. Texas and it gets very hot on the flagstone.