Took a look at my impeller - it looks like to newer unit in the FAQ... but I dont see any of those removable pieces. The only thing I could pull off was the blades. Everything else seems to be one unit. I dont see any o-ring or plastic collars. So I'm not sure if this is a cleaning issue. The driver alarms have been going off prior to this. I cleaned the pumps by soaking in vinegar and the driver alarms continued. Just tried soaking the impellers again, still nothing. Sometimes the multicontroller has lights on, indicating pumps are on, but they arent, and sometimes the multicontroller is completely off.