The film is caused by excess protein in the water. I just leave it be, it's basically harmless.
I usually have enough surface agitation that it prevents the film from getting to thick.
If the film is really bothering you, you can just get a new sheet of printer paper and skim it across the water every once and a while.
Another option, as mentioned above, is using an air stone. I've also seen filter intake attachments that suck in water through a skimmer (instead of being submersed) which would remove the film.
Fluval Chi 5G: Honey Gouramis, Betta, & Neon Tetra x4