The standard what is it thread?

[nzkiwi80]

Hoping someone can ID what this is and advise on the best way to deal with it. Seems harmless and I try scrub it off or suck it up weekly but it grows back

 

[Timfish]

It's cyanobacteria. Not beneficial but also ubiquitous and should be kept to a minimum. I use steel straws to siphon it out and paper towels to wipe it off glass if there's some noticable when I do water changes. With new systems, especially set up only with dry rock and bottled bacteria, it will be more abundant and take longer to cycle through. I'd add some wild or maricultured live rock if it was my tank, see Aquabiomics article