Need suggestions with two major problems

[Ruben's Reef]

I have an infestation of a million asterina startfish that eat all my zoas and once the light is off they came out from tiny ones to a quarter size big. Also, I have a green pocillopora that is growing everywhere and killing any other corals that stay in their path. Montiporas are getting out of hand also growing like weed. Thinking on getting ready of all the rocks and rebuilding the whole tank. What would be your suggestions? This is my tank at this time.

 

[Poshangcun]

You can use harlequin shrimp to eliminate asterina startfish.

 

[Ruben's Reef]

Yeah, I may need a few of them bc is a lot in my 100 g tank.

 

[Poshangcun]

Yeah, I may need a few of them bc is a lot in my 100 g tank.

I think a pair should be enough.