So the other day I was cleaning my canister filter and changing the carbon. I used this product (kent marine reef carbon) for the first time. I used the same volume as I normally do for regular carbon. I guess this stuff is very potent. When I awoke in the morning ALL of my acros were completely bleached white. The rest f the corals and inverts didn't look so good but they all survived. I didn't realize carbon could be so dangerous but I can't think of anything else that would have caused the die off.