I was wondering about the noise produced by the Aquaclear filters. I have several Whispers, and they are all quiet. I have one Aquaclear Mini, and it tends to buzz. Is it just a lemon? Also when I put CO2 into the Whisper it makes a racket each time a bubble hits the impeller. I no longer use that method. Does the Aquclear do the same? If so is there any way around it? I do like the rinsable sponge instead of the throw away filters.... Mike