Water Scum

[Delphinus]

Do you have a sump? One of the reasons for having a sump is to have that oil slick drain into the sump, get mixed up into the watrer colum and then be pulled out by the skimmer.

If you don't have a sump then maybe try an overflow box for the skimmer, that will help pull stuff off the water surface.

I think, in time, you will find that the Seaclone is an underpowered skimmer, and I have no idea what black powder is. Is that a Mark Weiss product????