Originally Posted by
spanko
Protein. You see it in the ocean along the shores, there is so much of it, it forms a foam along the shoreline.
This is why most run a protein skimmer to get rid of the excess as it is a nutrient that will feed unwanted algae.
Having it as a film on top of the water also shows that you have no turbulance on the water. You need to point an out put from your filter or a powerhead to the top just to create a slight turbulance.
So well put, it should be included in the "Helpful Threads" list.