What is this film on top of the water? PICS included

[floods7]

About 2 days ago i noticed a film that was on top of the water and it still has not gone away. I checked and the nitrate and amonia have not changed, still at respectable numbers. My nitrate is a little high around 15ppm but it has been like that for about a year now and i cant get it down.
The only thing that changed in the last week or so, was that I added Chemi-pure elite to my system. Maybe I didnt wash it out good enough before putting it in my filter? idk

 

[snakeblitz33]

Looks like the build up of proteins on the surface of the water.
Do you have a skimmer?
How often do you do water changes?

 

[1guydude]

+1 fat proteins! Or some kind or left overs... Point a powerhead towards the surface to get it under so the filter can catch it.... Best way to avoid it, Also a protein skimmer and a surface skimmer or spray bar would help you outs!
-d