I have a 55 Gallon FW tank. Using a Rena XP4. I have the suction from the RENA on one side and the Discharge on the other. I have a slime/oil/bubble film on the top of the tank?. It looks like the slime that beta's make on the water surface. This has started since I moved the suction/discharge on my RENA and removed the aeration. I did this for a reason, as I did not want as much water turbulence due to the fish I have. This however caused this slime on the water surface. I need something to remove this film on the top of the tank. My water parameters are great, water is clear & fish healthy. Can I use a cheep skimmer to remove this film.