If your tank is less than 6 months old, this is a stage that the tank must go through. Happens to every new tank. If those creatures mentioned above don't get it all, which they probably won't, then scrape it off. It should be sucked into your filter and then just clean your filter after it catches it all. Like they said, cut back your lighting and feed fish very sparingly. It'll get better. Are you using RO/DI water or tap water?