how to get rid of flatworms

[roblarss]

I had tried the 6 line wrasse but even in that small tank it cant keep up.
Only inhabitants in this tank is a decorator crab/really large hermit and until a few days ago a 6-line wrasse (jumped out while the cover was left off for an hour.

Im probably going to end up removing everything from the tank soon and try to dip the rock/coral.

My larger tank seems to have them around one rock off by itself and all throughout the sump/refuge.

Is there anything specific that causes an outbreak of these worms? I havent had a problem in my 120gal until now havent put anything new in there for many months. Cant think of anything in there that would eat them.

powder brown tang, tomato clown, bi-color angel, oscillaris clown, foxface, mandarin dragonette that I havent seen recently.