Algae needs nutrients to grow (along with light of course). If you are putting in more nutrients than you are taking out, you will see the signs (algae, cyano
, rises in nitrate, etc.). You need to evaluate your bio load, along with how much food (and supplements) you are putting in the tank V.S. how much you are removing. A better skimmer may very well be the answer. You will have to figure that out for yourself.
How much are you feeding and how many fish? What size are the fish? Water changes? What size system and what skimmer are you using now?