How much brown algae is to much?

[Studawg]

I know in a new tank that there will be some algea growth, but when should i start to take action against it, I am trying really hard right now to just live with it, my tank is about 4 weeks old and has live rock in it and nothing else. plus could anyone hook me up with some good pictures of drian tubes from plumbed tank. I am pretty new to this reef tank game so any help would be great.