Need help with this

[Jay uk]

There everywhere siphon some out, but they grow back so quickly

 

[Jay uk]

 

[Goss]

No Idea.

 

[billsreef]

It's a colonial tunicate. As for control, not much eats them that won't also devour your coral, so it's pretty much the old manual routine your already doing. Might be worth trying some kalk paste like with aiptasia, and seeing if that burns them out.