I am finally winning my battle with it. I removed the old sand bed, and replaced it with a 1/2" of florida LS, increased flow, raised my Mg to 1650, did 2 weeks of dosing algae fix, then started zeo vit. It is all but wiped out. The little left is clear and easily pulled off. It took a while, and some drastic measures, but the results look really good(crossing fingers). Oh, I also reduced feeding to the bare minimum.