I have 2 mak 4's. One ( the old one ) is louder and the new one is fairly quiet. Blue line makes a nice pump and is not too $$$ compared to the Iwaki. I also bought my skimmer from OA as well as the mak 4 and both are working very well. Anything with a cooling fan attached to it is going to make some noise. check out the Blue lines and Velocity pumps. FYI the Velocity will add some heat to your tank by a degree or 2 but they are very quiet. HTH
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