Is that a mesh top on your tank?
Looks like you should have bought one of these instead of a 2nd fluval. Surface scum really hurts your gas exchange. Itís one of the faults I found with internals. Hob types will pull scum down into water where filter pads will pick it up. Canisters are easy to hook a skimmer up to. But these days there are a lot internals that have skimmers built in.
Magnetic mount on this one is sweet.