I am having a problem where the alarm on one of my 6100's goes off intermitently. I have tried soaking it in vinegar and cleaning it to no avail. It will work for a few days and then the alarm will start going off again. I ordered a new impeller for it however the propeller on the one i received is larger than the original one and will not spin at all. I went ahead and changed the bushing inside the pump as well as the bearing and put the old impeller back in and still have the same problem. If there is anything you can think of please let me know.