Hello all I'm running a 13.5 Evo. I'm having problems getting rid of surface skum. I have a power head breaking the surface of the water. I am still using the factory foam filter however I have added a chemical pure elite bag to it. I do keep the water level kinda higher in all Chambers so I don't really get the surface skimming effect from the overflow. Im also run ning fluvals protein skimmer. I guess any suggestions would help?