Gunk in the back of my tank

[EvanDeVita]

Hi all,
I got new lights for my IM 30 Long AIO, and I’ve begun to notice algae growth in the central chamber of the back of the tank. Can anyone ID it and tell me how to remove it? It looks like GHA to me, but there is none in my tank. Can I add a snail to the back of my tank?
P.S. I have a lot of sponge in the back chamber too.

 

[EvanDeVita]

Photo taken under 100% white light (not my normal spectrum). Usuall has a brownish tint to it that my camera can’t pick up too well.