My GE PDWT580P00SS dishwasher was not cleaning on the bottom. I determined that the bottom and middle spray arms were not turning. I removed them both and cleaned them out and they appeared to be turning after that, but now the bottom is not turning again. I checked to make sure water was coming to the bottom by placing a solo cup over the bottom center to see if it got blown off or not. It did. I noticed that the bottom arm seems to fit loose. Any ideas would be appreciated.