What kind of algae is this?

[Jlmiller1057]

Hello,
I just started up a 90 gallon tank. It has a built in overflow and I am running an octopus skimmer in the sump. I have sand and macroalgae in the refugium and I am using Seachem purigen and carbon right now and I am going to put in chemipure elite soon. I have a lawnmower blenny, a clown, and a firefish. I bought a clean up crew online and ever since then this brownish blackish algae has started growing on my rock. My tank already went through the cycling process so Im not sure if it is diatoms. It isn't easy to wipe off either but it is coming in little spots so it is hard to tell what it is. I do have some pink coralline algae starting to grow on my overflow box and my powerheads. Can anybody help me identify what algae this is? Oh yea my silicates and phosphates are high I think because I have a ton of those pineapple sponges growing in my fuge.

It looks kind of purplish in the pictures but that is because of the light. It is more of a brownish color. At first it looked black though.

[/ATTACH]

 

[Mebbid]

Brown is a primary characteristic of diatoms and they can easily happen regardless of whether the tank is cycled or not. Don't worry though it will wear itself out in due time.

 

[Ricksreef]

It looks to me to be Coraline algae in it's early stages.