Biznas, I don't think you need a suface skimmer, I don't know anyone that uses them in planted tanks, I may be wrong though. All I do is move the spraybar from my outlet closer to the surface of the water. It will give some circulation at the top which should help break up the film and some surface disturbance is good for oxygen levels. If this doesn't take care of it you might want to find out why you have so much scum in the water, overfeeding, dying plant material that is not removed, etc. This might be an indication of high TDS (total dissolved solids)/organic compunds in the water. If these build up they can be very harmful to the flora of the tank. How often and how much does the water get changed?