The noise is when the prop pushes out instead of being pulled in. The prop hits the front of the housing and makes a racket. Some of the ones made have a piece in front that forces the prop back down when this happens.
I would not use one on a wave timer but I have one that I shut down at night and start back up when the lights come on.
A modded MJ1200 will outflow a K4 IMO
. Mine all do. Put the big MJ prop in the K4 though and it evens things out
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,