Since the number of cherries has risen in my tank due to them breeding it seems the amount of oily film on the surface of the tank has increased. I’m now thinking of getting something like the Eheim Skim 350. I don’t ideally want it in there permanently though. Have any of you used a skimmer on an occasional basis, say just using it once a week for an hour or so? I can’t help wondering if there’s a gap in the market for a hand held skimmer that can be used as required. Something like the gravel cleaners that are available but designed for skimming the surface instead.