What's with the black stuff?

[Brian Kennedy]

My tank is a 72g bowfront and is about 2 months old. I Cycled using Dr Tim's fishless method. I set up a 20g long fuge with chaeto that's growing well and pods from algae barn. I’ve have mild gha and some brown diatoms but much less since adding the pods and chaeto. Overall the tank looks good. I’ve probably got 60 pounds of live rock and Caribsea life rock with correline growing nicely.

Ammonia = 0
Nitrite = 0
Nitrates = 0
Sg = 1.023
pH = 8.2

I noticed this black stuff on one of the rocks that I can’t identify. There was a quarter size piece in the five, but I removed it. Any thoughts?

 

[James M]

colospongia auris, it’s a type of sponge . You should get rid of it , it’s invasive

 

[Brian Kennedy]

Best way to eliminate it?

 

[James M]

Best way to eliminate it?

Scrap it off

 

[Brian Kennedy]

A friend told me it might be cyano. Being a new tank I wouldn't be surprised, but it just doesn't look like anything I've found in the threads.

 

[James M]

https://www.reef2reef.com/threads/black-algae-need-help.221031/