I have a couple random questions about my 20g..
I have some hair algae growing and it's been touching The frog spawn.. The coral doesn't seem to be bothered, it opens normally every day.. But I just wanted to make sure. Here's a picture
I've also seen this black.grow in the past few weeks

Any idea what it is?
Also what are these white things on the back glass? Are they harmful? They've been there for a while..


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