I doubt it's necessary to recirculate pbw through it. At the end of the the transfer to your fermenter, there's wort and maybe debris in there. If you flush it with water immediately afterwards, without giving it time to harden, it should be clean. And if you recirculate hot wort before chilling, it should be sanitary.
Nevertheless, I do use oxiclean after each brew. Since I'm recirculating anyway, it's no extra effort.
Nevertheless, I do use oxiclean after each brew. Since I'm recirculating anyway, it's no extra effort.