hey- i just bought an aquaclear 70 off ebay new for 38 bucks. it runs good and is very strong on my tank, but it's noisy. the impeller is loud. i have an aquaclear 50 and it is whisper silent, no noise from the impeller at all. is this noise temporary, like the motor and impeller are breaking themselves in? also,the hood was rattling, so i removed it. any ideas on what the problem is? by the way, what media setup do you fellows use? it came with a foam, carbon , and clay rings, but those only take up like 1/2 the media basket!!! so what do you guys do? thanks!!