Check out this video to learn how to swap out your capsule shells.
If you got podpoi before May 2013, you might have "short" or "donut" capsules. You can get the current longer capsule shells here that are slightly longer and can hold a knot+washer inside.
If you need capsule shells that have been modified to fit FPC rope, we offer them here: https://flowtoys.com/capsule-shell-modified-for-fpc
If you have any questions, please feel free to contact us!