Help identify this stuff please

[MapleLeafReefer]

Hello. I bought a used tank and in the overflow I found this white substance. Its getting larger at a fairly fast rate. I'm almost certain it should go but before I get rid of it any help identifying it would be grand. Any ideas on best way to remove would also be helpful and welcome. Thanks in advance

 

[Saltyreef]

Looks like a bacteria.
I have some in the cryptic zones of my sump as well.
I just siphon it out during water changes

 

[MapleLeafReefer]

Cool. Just mixing up some water for a change in the next day or two. I'll get it sucked out then. Thank you