He is now a CopperPoxy distributor, one of several nationwide. The marine life is not poisoned, but elects to find other digs. Soft growth will gradually build up on the hull but, according to the manufacturer, routine maintenance will take care of that. Because the coating is so hard, the hull can be scrubbed to remove the soft growth, which will maintain the compound's effectiveness. And, because it is nonsloughing, scrubbing will not release foreign elements into the water, hurting local marine life.
Coral reefs are especially sensitive to such releases.
Simply, it depends on how fast the grass grows. If it is applied properly, I don't see why it should have a life span. It should last a long time. The compound will eliminate the routine bottom painting of the fitting out season. You might need to restore the thickness if you've done lots of sanding, but that's all.