Barbara;183269 wrote: William, are you thinking of doing this simply because it is easier to cut and glue the 4 walls versus finding a round cylinder of acrylic? I don't know an awful lot about skimmer types, but it does seem to me that you'd get better performance out of a round one. Although if you're going to put 3 pumps on it to recirc, round versus square might not be an issue with that much flow.