if you ever look at the bubble at night, it lets out tentacles. Think thats part of the problem i think with the bubble/frags but i haven't seen your tank up close so.
Also whats your lighting, your levels of the tank, how long its been set up...blah blah... u know the deal Duke =0P without any of that info we can;t tell you how to stop the green algae or whats going on with the frags. Better up close picture also of them would help.
algae could be PO4 problem (you will know if your testing with a good test, instant ocean doesn;t work) Algae grows due to high nutrients, high Po4 levels, low flow, alot of factors. If your talking about the algae in the sand, people usually get it as the tank matures along with high Po4. Also after you correct the problem make sure you scrape it well and move the sand thats touching/around it.