I keep adding up the costs vs. the benefits and I just see N2 as a waste of money and potentially a problem.

If you can run the unit without the cartridge without it leaking, then it should have no effect on the pool and you won't need to cut it out of the system.

But, as I've repeated, $90 per season for a cartridge buys a LOT of bleach!--not to mention it will buy 6 or more quarts of Polyquat--MORE than enough for a season!