Hello,
I was wondering if the ''Lee's counter current skimmer'' would be good for a 20 gallon with either a 5.5 gallon sump or a 10 gallon sump?
Also, the skimmer would be in the sump.
I used one in a 10 gallon once and if I remember correctly I had to cut about an inch off of the length, after that it worked fine. I may not have had the smallest model though, I can't be sure. HTH, Skip
I've got the pico version of this type of skimmer in my wife's tank. It works pretty well. You do need to use limewood airstones with it, and they need to be changed a couple times a month.