How do you, if you do?

I looked into mine the other day and they are filled with algae and aptasia.... I had a little aptasia problem in the DT but a little kalk paste and some peppermints is doing the trick slowly....

I am afraid to scrape the inside over the 2 overflows and start a outbreak....

Should I leave it as long as they are not interfering with the flow?

Should I make some black acrylic covers to block light? Doubt it would help with the aptasia but limit the growth on algae .