I recently purchased a 40 gallon tank off craigslist with stand, heater, filter, light, etc. It was a pretty good deal for $75 bucks. When I got the aquaclear 110 running that came with it, it made a terrible rattling, grinding noise. I read up on some forums and decided to replace the shaft and impeller shaft on it (they were pretty worn out). I thought this would for sure solve the problem but when I got all of the new parts in, it still made a noise (although it wasn't as bad). I maybe would be okay with the slight new rattle it made but I keep this tank in my room so the noise is unbearable when I am trying to sleep. So I trying taking it all apart once more and I cleaned it out with water and put Vaseline on the impeller/shaft. This worked great for about 10 minutes before the Vaseline rubbed off, now it is back to the same rattling/grinding noise it made before. The only thing I know to do now is order a whole new motor, but I am scared that even that won't solve my problem. The filter cleans the water great but I don't know what to do at this point. ANY HELP is appreciated, I'm DESPERATE to get rid of this noise.