The ‘Ionizing’ light should flash if there is material left on the mineral plates and there is current travelling from one plate to the other.

There are a few possible causes for this:

1) The mineral plates have worn down beyond useful life.

2) The mineral plates are not fully immersed in water. In this case, the current cannot travel from one plate to the other so the Ionizing light does not flash.

3) The pink plug on the electrode cable is not fully connected into the pink connector on the controller.