Water softener installed Nov. 14, 2008, and seems to have operated as designed since then. Noticed recently that during regeneration, when the cycle leaves stage C4 (System Pause) and entering C5 (Fast Rinse Cycle 1) there is a short, intense water pipe rattling. I’m not sure how long this has been happening since I was usually at work during the scheduled 1AM regeneration. I have also noticed the the water level in the salt storage tank is barely up to the salt, and I keep the salt level low in case I need to move the tank for access to the water heater. I tried to contact the supplier and installer (who I really liked and trusted, all they did was water softeners) but the owner has sold the business and I haven’t heard anything positive about new new company. So, I need to know if the salt tank water level is a problem. The water seems to be as soft as the day it was installed but, I am also wondering about the condition of the resin. Advice will be greatly appreciated.