Stubborn Protein Film

[JohnnyReeftank]

Ya I have the same problem on my 35g. Its a common problem if your tank doesn't have an overflow because the surface never really gets filtered. I tried the surface skimmer with my old skimmer but it doesn't really fit my newer one. I've noticed that it goes away as long as my skimmer cup doesn't overflow so I've been pretty diligent with emptying and cleaning it and it seems to appear a lot less often.