Just an update -- the FX5 is back to life! It sat in the corner, empty, for a couple of weeks. Then my husband took off the motor and looked for debris. There was none. He put it back on and filled it back up with the media (we had it sitting in the filter part of our pond so bacteria didn't die) and it worked! I'm glad it's back with us, but I'm also glad we run multiple canisters on my larger tanks, otherwise, we'd have been in trouble.