Need help IDing in my dads tank

[Redlaxer2022]

Hi! My dad hit me up recently saying he had this stuff growing all over his tank and I honestly had no clue what it was and how to get rid of it. He said his LFS told him it was seaweed? And he just needed to pull it all out when he did his water change but there’s been no luck. If anyone knows that this stuff is and potentially how to get rid of it my dad and I would greatly appreciate it

 

[tbrown]

It's really hard to tell from the pictures.

Green or red?

Does it grow in little strands like GHA or in flat blades like Ulva?