For some reason i am getting a film on the surface of the water. it seems like my surface skimmer is not working right. I am running the hydor flow which rotates and does agitate the water surface but that isnt helping either. I tried to lower the water level in the main tank, that still didnt work. so i dont know what is going on.
try blocking the lower part of you surface skimmer so that it has to pull from the top. Also try doing a search for the "cassette surface skimmer" mod. I have heard of people complaining about this and that seems to be the ticket.