Every time i sweep a string and then pull off, it plays the open note and makes my sweeping sound messy. can i somehow not play that open note?
mute with your picking hand as you sweep
Lift your finger directly off the string, don't twang it like a pull off.
...practice with a metronome in a slow setting. Increase when you become accurate.
try advance technique because sweeping is considered a mediocre skill lvl and higher