My oldest FX5 filter suddenly quit after maintenance early this week. Was working fine and when plugged in after cleaning it made a slight rumble and then died. No impeller noice so I assume its the pump. The filter is 11 years old and has been runniing continuously. I replaced it with a brand new FX6. The old filter is otherwise in decent shape.....I found replacement pump assembly for about 180 bucks........is the repair easy? worth the cash? i figure its really the only moving parts. I am thinking about fixing it down the line.....anyone have experience with this? TY