I have been using Brightwell for about a year now. My tank was doing really well and in about July of last year I started loosing some large colonies of established sps. Some of the colonies "bleach" out virtually over night,some start bleaching then stop for a short while and then completely go, other colonies are totally unaffected. I am at a loss for what could be causing this. The only thing that has changed is the salt I am using. I personally don't think that, that is the issue, but am at a loss right now,so trying to see if anyone else has had issues.