Systems and methods for controlling chlorinators for pools and spas are provided. A controller communicates with a processor positioned within a replaceable cell cartridge of a chlorinator, to allow for remote control and diagnosis of the chlorinator and/or cell cartridge. The cell cartridge stores, in non-volatile memory on board the cartridge, one or more parameters associated with the cartridge. The controller can obtain this information from the processor of the cell cartridge, and can use same to configure operation of the chlorinator. Information relating to remaining cell life can be updated by the controller and stored in the non-volatile memory of the cell cartridge. Electrical and software-based mechanisms are provided for ensuring operation of only compatible cell cartridges with the chlorinator. A system for remotely diagnosing errors associated with the chlorinator is also provided.