There is no fixed size of pot for
ebb and flow system. It depends on two factors i.e. how much light you have and other one is Area. Still with an example shown below you can get an idea what should be the pot size. For example: In a 4*4 feet area, running a 1000watt light, you can grow 10 to 30 plants. If plants are smaller at the time of flowering then we can have more space for growing other plants.