1. It's not a proc (procs are the fancy colours that suddenly lights up cause you are hitting a mob), but effect. Effects are either right-clickable (used like a spell of sorts) or they are permanent (i.e you don't have to do anything to start it). This is a permanent effect like that.
2. "Flowing Through I" gives wielder 1 extra mana per tick; compared to Clarity II which gives you a max of 11 mana per tick. One tick is about 6 seconds.