The reason I'm such a believer in them now, is when I worked at oasis, we had a tang in the frag tank that was looking really really bad. Color faded and blotchy. He just didn't look good. He was eating like a pig, swimming great and we tried everything. We decided as a last ditch effort to toss a grounding probe in tank just for S and giggles to see what happened. It was honestly like a miracle. Within about a week, the fish had his color back and was looking outstanding. Was it the Grounding probe????? I don't know and can't say for sure but the evidence pointed in that direction. Now I will not have a tank without one.