How to tell if water softener works OK?

I have a Culligan Model 89 in which the control head has been rebuilt and regasketed and the resin cleaned by Culligan. I mule hauled the unit to local shop to save a big house call travel expense and then reinstalled the unit. I recharged the unit daily for several days. The salt level in the brine tank does not seem to be going down. A quarter inch stream of water is coming out of the drain hose during recharge.

It worked fine for many, many years.

What checks can I make to determine whether the unit is operating properly, such as water softness, mechanical tests, etc.?

Thanks bunches!