There is research out there that shows that a combination of silver ions and chlorine together make an incredible combination in fighting all sorts of bugs in water. The silver weakens the outer shell of bacteria and chlorine just explodes what is left. Whether the N2 stick provides enough silver to do a credible job is open to discussion and of course you don't need the silver for chorine to do a good job, but it sure makes sense explaining the ability to sanitize with a lower free chlorine level.