All PVC lines will crack at this point. ALL OF THEM. Good old, nasty, rotten and ugly 50# braided mono loops solve the problem. At least slow it down big time. Don't coat them with anything, stiffening is what causes the lines to bend repeatedly in the same spot...which is why welded loops always crack in the same spot. If you are worried about the welded loops breaking where the core is exposed...cut them off and go braided. Or fish them. All of mine are cracked and one of these years I will get around to cutting them off and replacing them with non coated braided. Maybe.