You are looking at the back glass of my refugium. IMO the coraline is hosting the spider web looking red stuff. In the regions where the red stuff has covered the coraline, the coraline starts to bulge and can be scraped off with a finger nail. Does any body know what the red stuff is? It is not cynobacteria. It has a semi rigid structure and is not easily remove, it is imbeded in the coraline. Please let me know what you know about this stuff.
Thanks
Thanks