Building my first big aquascape for a 120g reef aquarium (>100 lbs rock). I've finished my first section of using motor. I ended up with a lot of the Marco rocks (40 - 50%) coated with the grey mortar. I've seen others apply cyanocrylate then sprinkle with reef matching sand. I'm thinking a faster and more uniform method would be to use two-part epoxy(used in my pond) which would be easy to brush on and cover with sand. I wanted to get any input before going with this method....any downsides?