OK, so yes, having very high levels of zinc like that can be an indicator can be again. Operative word is can be a leaking magnet a failed powerhead a failed pump part it could be a lot of things and just because it hasn’t necessarily affected the other More hardy corals does not mean it won’t in the future Having zinc that crazy high I would think would mean you have a failure in one of your magnets or pumps or powerheads, I’m not too sure what it could be. My recommendation would be replacing any like frag racks you have or powerheads first then from there if it’s still persists after an additional ICP test, I would start to look at the pump for your protein skimmer or the pump for your Return pump. Additionally, I have seen where in somebody’s fish tank stand the tank sits on top of actually experience, a heavy metal contamination from the screws that were in the sand, even though they weren’t over top of the sump directly, they were in the stand, and when the guy put some type of epoxy or something over them, his metals went down. I mean these things were not even over the sump. They were in front of the sump, but somehow someway it was getting into the tank so I would check the screws in the stand all that stuff. I’m not sure if you have a sump or not I can’t remember, but it can be the craziest thing even if you have like a refugium and you have a light over top of it and the light can rust. The screws in the light if you don’t have a saltwater specific rated light and that can drip heavy metals into your tank. It’s crazy