I suggest cleaning in the controler. In the manual, note the cleaning that they recommend annually. I would not do that annually, but include those things. I would do more, and in your case I would particularly try to clean the brine refill control. Get silicone grease. Note in particular the section called preventive maintenance. I would go even further. I would pull the cam, clean the flappers, apply light silicone grease, and put them back reversed from their current positions.
I got a tube off MolyKote 111. It is thick. It lasts a long time. Wear nitrile gloves when applying silicone grease. Q-tips are useful for cleaning and applying grease.
I have an Autotrol 1550-TC which is like the 155.