How to get rid of stinging hydroids?

[FOREIGNER]

Hello everyone, I have been observing my tank at night and discovered numerous "string-like" tentacles that come up with little bristles on the sides of them. I have done some research and I have heard they are either stinging hydroids or some sort of worm. Point is I have a few and I am moving to a larger tank and thought this might be an opportunity to get rid of them. Any ideas how? Could I dip my live rock in something? I thought about manual removal but they the tentacles seem to be deep inside holes in live rock and retract with any light.

 

[myDigitaLife]

I have the same problem and would love an answer to this post.
I've heard that there are some species of nudibranchs that feast on hydroids...not sure if they are reef safe or available to the hobby.