Posted: Thu Jan 12, 2006 8:04 pm
The film is a build up of proteins and other substances, and is most noticeable if the water surface isn't being moved. Submersible filters such as yours also aren't the best, but moving the outlet so that the water circulates better and moves the surface will help (but I've noticed with these kind of filters that films will also form rather quickly if the filter isn't also kept really clean). Feeding your turtle outside the tank in a separate container if you're not doing so already would also help.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-