Have you check the driver (silver box) make sure there is no salt build up inside. I know it sound crazy but i have seen one of my friend has his driver mounted inside the stand and it has the same problem. When we take the drive apart, everything was covered with salt. Does the alarm goes off at all? How often do you clean it? What condition is your impeller and motor block? May be you should try some vinegar, inspect your driver box for unusual sign....
I hope you aware of the warranty policy..... 2yrs on the pump