Final week or so... Flushing tonight

This is my first grow and I'm planning on flushing tonight. I'm at about 9 weeks of flowering, so my question is this: do I just use plain tap water? I bought a flushing medium, but I'm not sure if thats strictly for nute locks or would benefit the final flush. Any ideas? Sorry if this has been answered before....

a flushing medium???

use water and 'Clearex'. thats what i use. i like to do a 2 week final flush. U can get away with one week if u gotta. But if you have the time and arent in a rush then do the 2 week flush

yeah I have clearex as well... just wasn't sure if it was right to use for final flushing. I did a water only flush last night, but maybe in a few days i'll do one more with clearex