ID please?

[laurenseitz]

So within the past couple days, I noticed a couple of these spots forming on the side of the glass. Just wondering what it is, I cleaned a couple off... But was curious as to whether I should leave it if it's beneficial.

 

[cloak]

If it's kind of hard to remove then it's probably coralline algae. This comes in all kinds of different colors.

 

[laurenseitz]

Okay thanks! I always thought that was more of a reddish color, but it is harder to get off!! Thanks!

 

[tehpineapple]

I've got a lot of that on one of my tanks and starting to get it on my second tank too. It's definitely coralline. Some of the green eventually turned a pinkish red. Really cool looking stuff.