vortech

[xtreme]

I wouldn't say they are loud, but you can definitely hear them running. Especially in pulse mode.

[mike31154]

I started with one MP40W in my 77 gal and added a second one about a year later. Two are great in there, you should not have an issue with one whatsoever. Each one of mine sounds a bit different. I'd say the newer one is a little quieter. I find neither of them obtrusive with regard to sound, it's there, but generally fades into other ambient noise in the room.

[Doug]

I have two MP 20,s in my 30g cube sps tank