I have a hob filter that is extremely noisy. I have noticed it more in the past week or two. In the last month or more i have came home to the filter completly stopped. I would just nudge it and it would kick back in. It sounds like a grinding sound. Can you buy new impelors for your filters? Does anyone think this is why its making so much darn noise! Its probably not the greatest quality filter, its a whisper 60, or somehting like that.