Possible new in ground pool w/ Nature II

[CarlD]

Furthermore your annual cost for the N2 cartridge will NOT be offset by your savings on chlorine. It doesn't replace chlorine, just reduces the amount you need, hopefully, by killing algae that uses up chlorine that you need to sanitize the dangerous stuff like bacteria.

[waterbear]

I bet the contractor sells the replacement carts for the N2. It is a big moneymaker at two carts a year! (I know, used to sell them!)