When using a mono running line, sooner or later you may encounter some amount of line twist. This is often caused by a spinning fly, or by making the same cast again over and over. Check out this tip from Ed Ward on how to quickly fix a twisted line. You can also let the twisted line straighten out in the current downstream of you. In really bad cases you can also just cut off the problem section- a spool of Lazar Line is 50 meters so there is plenty of extra.