I have a frag of monti that's been engrusting a frag disk. I want place it so it hangs off over the edge of a rock. How should i do that? The rock has some algea growth. Should i just pop the frag off the disc and use the molding clay? Any ideas would be appreciated.

What kind of montipora is it? If it's been encrusting onto the plug I wouldn't remove it, but you can just glue it down wherever you want. I'd remove the algae, but it'll grow back until you address the root cause of it unfortunately.