What kind of algae is it?
Do you have your water parameters handy? Knowing those would help us to make recommendations, it would be very helpful to know your levels of the following:
Ammonia
Nitrite
Nitrate
Phosphate
pH
Alkalinity
Magnesium
Calcium
More questions...
Is this a fish only tank or do you have corals/other inverts as well?
What kind of filtration are you using?
What lighting do you have?
Are you using live rock, dry rock or a combination of the two?
How long has the tank been set up?