when you do water changes, use a small glass bowl to scoop some of the discard water out of the tank. first, turn off all the pumps and let the water sit still for a few minutes. then, carefully put the bowl into the water so the water slowly pours over the surface into the bowl. it will skim the top surface of the water. it won't take too many bowls of water to get the surface completely cleared up. i do this on my tank since i am not running a skimmer and it keeps the surface nice and clean - in essence, be a human skimmer