Can anyone help me I’d this film growing on my rocks and how to get rid of it. 3 different colors

[Johnnyrainbowreefer]

I’ve attached some pics. It’s not out of control but I. Want to nip it in the bud whatever it is. I’ve attached pics of it. It’s rusty colored, red, and purple on one spot. It’s not cyano, and not coraline. Thank you

 

[Timfish]

Looks like sponges to me, I'd leave them. Sponges are essential recyclers in reef systems and process DOCs much, much faster than bacterioplankton.