The last penguin I got was noisy out of the box, all of my emperors are old. IME both usually start off fairly quiet (just little bit of waterfall noise from the biowheels) and get noisier (vibration noise) after running a few years. A new impeller with often quiet them.
Aquaclears are reputed to be quieter, but I got HOT magnums for my bedroom tanks. In general, canisters are quieter that HOBs.
aquaclear filters are about as quiet as it gets with HOB types......and canisters are considerably more quiet....
but i have found that after a short time i find the noise of the water movement quite soothing and allows me to get better rest...
Marineland Emperor and Penguin ?
Linear Mode
