Help with whatever this is

[Ladyocto]

Hello Everyone!
Not sure if this is the right spot to post this as I don't have a reef tank, just saltwater, so I hope this is an okay spot to post and if it's not I apologize.
So I've had this stuff growing in my tank for a little while and at first it was just a tiny patch and I didn't think much of it, but now it's starting to spread. Any ideas on what it is? I've been looking online and found suff that's similar, but nothing that I feel is an exact match. The closest I've found is that it might be some kind of Hydroids?

 

[Crabs McJones]

Yup, hydroids. They tend to die out as a tank gets older and matures

 

[ISpeakForTheSeas]

Yeah, definitely hydroids:

I've heard smothering the hydroids with kalk paste may work, but here are some other threads with suggestions that might be helpful:
https://www.reef2reef.com/threads/hydroids-a-reference-to-some-strategies.819522/https://www.reef2reef.com/threads/hydroids-how-do-i-eliminate-they-have-taken-over-my-tank.329188/

https://www.reef2reef.com/threads/fenbendazole-dip-for-blue-clove-polyp-hydroids.1020246/Edit: A relevant link in post 7 of the link above:
https://www.reef2reef.com/threads/here-it-is-fenbendazole-use-against-hydroids.214950/

 

[Ladyocto]

Oh crud . I probably should have been expecting it because my tank isn't quite a year yet, but I had been very fortunate for months without any issues like this. I have been adding a lot to my tank recently though so I'm guessing that's where they came from. Thank you both @ISpeakForTheSeas @Crabs McJones very much for the response and thank you @ISpeakForTheSeas for the links!