Need help to ID this algae. At least I assume it's algae. My LFS didn't know what it was ( didn't have a pic to show them, just a description) and I can not find it on Google. I just switched over from a 65 gal to a 90. No problems in the previous tank. This showed up about 4 days ago, and is growing fast. It is flat, and gray. It doesn't look very gray in pics,
