Noticed some new bubbles

[Brisc0]

Hello, I notice that I have a good bit of bubbles stuck to my back glass. I guess I never saw them before the MHs or they are new. Anything to be concerned with? Thanks!

 

[reefrunner69]

air bubbles? Algae bubbles? etc...

 

[quarryshark]

I have the same, I think that the bubbles are getting caught by the algae growing on the back side of my tank.