What does No Flow mean on my salt system?

There is a flow switch inside the salt cell. When water flows over that switch, it will tell the salt cell that it is safe to produce chlorine. If there is not enough water going across the flow switch, the sensor is not tripped and you will get a low flow indicator. If there is anything causing a low water flow to the pump/cell, such as a dirty, leaf filled skimmer basket, this could create the No Flow issue. Other causes could be a dirty filter or a dirty or clogged salt cell. Make sure your filters, cell, and baskets are all clean and not obstructing the flow before assuming that your flow sensor is bad.