Need Help ID'ing some growth

[cichlid.greenhorn]

First pic on the right side of the green rock.

Second pic growing all over intake tube.

It's greyish in color. South American predator tank. Java fern only plants, 10 hrs of light daily.

Any ideas? Should I just pull it out and clean or is it harmless? Been growing about two weeks now.

 

[fort384]

Not sure what it is. Could it be BGA on the rock?

If it comes off easily with a brush, I would clean it off, and see if it comes back.