I pulsed the motor a few times to see how loud it was comparing it to the 1/3rd sized 4200 ( Dart equivalent almost) & surprisingly it seemed to be very quite, I think I'll have to recycle water back into the sump to keep up though, this should be fine because now I can plumb a header to supply whatever I need like, skimmer, carbon/phosphate reactor & eventually CA reactor, I won't need any other PH's or pumps. I think if I misjudged anything it would be the CL pump, I could of gone to the largest reeflow series or the 1,000 series & it would of worked out better using 3/4" loc-line, instead I reduced to 1/2" with a "Y" on top & a straight 1/2" outlet on the bottom, snug fitted also, looks like it will produce enough flow along with the sump return, guess live & learn. Funny thing the WaHoo is called the 3,000 series, I think they just slapped on the salt water seals on a 3,000 & made a new line, they say the three UNO series is rated for tanks between 50G & 200G, I have to beg to differ, I think you could go all the way up to a MoJo sized tank with one of these for sump circulation, 32' of head is plenty & they have one larger LOL