Abstract: A customizable pool automation control system includes a system housing defining a protective enclosure. A processor is located within the housing. A plurality of expansion slots are formed with the housing, and operatively communicate with the processor. A plurality of modular external expansion cards are adapted for being custom selected by a user and inserted into respective expansion slots. The expansion cards are selected from a group consisting of a chlorine generator control, a water level control, a camera control, a valve actuator control, and a relay control.