Well, the advice I've seen given on this thread is a little jumbled up, so we should straighten things out.
1.) Carbon doesn't need to be changed every week. Not sure where that came from.. Normally it can last 4-6 weeks depending on the type.
2.) An algae bloom generally refers to diatoms and such that appear during/after the cycle. In this case it would be a Cyano outbreak.
3.) Skimmers are not required on tanks this small.
4.) Guys, you can't judge how much rock in weight someone has through a picture. There may be plenty of small holes in those rocks that we can't see here were bacteria is colonizing. If I were to judge by the picture
Middle coral skeleton- 3lbs
Left Rock- 4.5lbs
Right Rock- 4lbs.
Which gets us past 10lbs. Maybe the OP just prefers a minimalist look.
5.) Red Slime = Cyano
6.) I'm guessing that he has an RO/DI unit plumbed into a faucet, so that's where he gets the water from.
MY ADVICE:
Move the clown, they get up to 6" and the bioload from him his fueling nitrates for the algae.
Get a powerhead, a Koralia 240 or 425 will do you good.
Decrease feeding and lighting, and up the water changes.
Make sure the tank IS NOT in direct sunlight.