New to reefing

[OsuMarine]

Hey guys, I’ve had my tank up and running for about 3 months now. I’ve got something growing in my tank that has been here for a few weeks now. Do I need to do something before this gets out of hand. I do a weekly water change of 4 gallons. My tank is a fluval 13.5 gallon. I’m running filter floss GAC and a lot of bio max media. Any information would be appreciated.
Thanks!

 

[AydenLincoln]

What are you referring to? And do you have a cuc like snails and hermits? And some of it looks like the normal uglies in a new tank.

 

[OsuMarine]

What are you referring to? And do you have a cuc like snails and hermits? And some of it looks like the normal uglies in a new tank.

The yellowish/brown stuff on the glass. I have 3 nassarius snail and an emerald crab. I also have a diamond goby.