Any idea what algae this is?

[chrisgold]

This seems to be sprouting off my rocks and some of my sandbed

 

[ISpeakForTheSeas]

This seems to be sprouting off my rocks and some of my sandbed

Are they flat, or tubular?

If tubular:

Possibly a Lychaete sp.? For example:
https://www.reeflex.net/tiere/14642_Lychaete_herpestica.htmIf not, I'd lean toward it being something else from that family (Cladophoraceae) like a Cladophora species. For example:
https://www.marinelifephotography.com/marine/seaweeds/cladophora-catenata.htm

 

[chrisgold]

Are they flat, or tubular?

If tubular:

Any idea how to get rid?

 

[Subsea]

You asked any idea what algae this is?

To better answer what algae, I ask you, “Where did the rock and substrate come from”?

 

[chrisgold]

You asked any idea what algae this is?

To better answer what algae, I ask you, “Where did the rock and substrate come from”?

It started as a dry scape I got made

 

[Subsea]

That is some good looking rock you got made.

What other livestock is in the tank? I noticed that you used 12% peroxide which is what I use for nuisance algae control. Tell me more about how you used it.

 

[ISpeakForTheSeas]

Any idea how to get rid?

No - the only critters that I know eat the stuff are meiofauna (like pods), so they don't eat it fast enough to effectively control it.