Recovery pumps and column size

We picked up a trs600 at a great price for our closed loop, and it was a night and day difference from doing it passively. Killing it on the little 73g column. However, yields were terrible on two runs with a 200g column. We were told the pump might not be big enough for that column. I'm finding no information on recovery pump size relative to column size. Everything being equal, we can't figure out why there was such a big % difference in yield between the two columns. Hate to run that much material for another lousy yield. We really don't produce that much. Is this recovery pump story viable?

Thanks for your time....