Ok, my second MP40QD had had the magnet covering fail and then rust and split open. I never had an issue with the original MP40's. I only use vinegar to clean.?The first sign this happens is the wetside stops turning and then you obviously see the rust. My first failure was about a year after buying and my second failed about a year and a couple of months.?Could be coincidence but I had some SPS dieing so I am running carbon in a reactor.?So far echotech has not given me any grief over replacing even though out of warranty so I wonder if they know there is an issue ? And is it a bad batch or bad design ? I would have thought by encasing the magnet in plastic it would have been completely safe but I assume the plastic is opening up at a seam.