How much flow do you have in the tank? What are your water parameters?
pH,
alk, cal, nitrate, phosphate?
Alk and calcium doesn't really have a lot to do with the
cyano (that's what it sounds like you may have), but it does promote the growth of coraline. The more coraline you have, typically the less of the "problem" algaes you'll see.
Nitrate and phosphate are used as food by the algae.
Cyano often will not do well in direct current either.
You might try running just the actinics for a few days. I've never tried this, but I remember reading a post by another member whom I believe had success with this method. Might be best to verify this before you do it though.
HTH.