i bought a mak4 and its been on for a few weeks, until i find a new one to replace it with. i tried to take the fan off and it was still loud. i built an insulated box around it and that made it not as loud, but still anoying. if it burns up its no big lose to me, then i will be forced to buy a new one. in case thats not clear enough i hate MINE and wish i never bought it.
just to be fair to the pump. some people love them and say they are quite as stated by someone above. its got great flow, and the price is right. i would suggest if you want to get one try to hear it run before you buy it. some are loud and some are not
other than the noise its a good pump. puts out good flow, and has run nonstop for three weeks wraped in an insulated box with any problems