How to clean a Corner-FLO overflow

[savetheocean]

This weekend I am hoping to clean out my whole tank and one thing that has been bugging me is all the brown coralline algae and white little dots all over the corner drainage area. I tried with an old card to get the filter feeders off but wasn't too successful. Any suggestions? Hopefully, you know what I am talking about (If not ill post a picture).

 

[vic5hands]

i would leave it aloe. The tank is maturing.